Error(s) in re-building vignettes:
--- re-building ‘help.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/crayon_1.3.4.tgz'
Content type 'application/x-gzip' length 750230 bytes (732 KB)
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downloaded 732 KB

trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/digest_0.6.18.tgz'
Content type 'application/x-gzip' length 188369 bytes (183 KB)
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downloaded 183 KB

trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/magrittr_1.5.tgz'
Content type 'application/x-gzip' length 155017 bytes (151 KB)
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downloaded 151 KB

trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/praise_1.0.0.tgz'
Content type 'application/x-gzip' length 16397 bytes (16 KB)
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downloaded 16 KB

trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/R6_2.4.0.tgz'
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downloaded 55 KB

trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/withr_2.1.2.tgz'
Content type 'application/x-gzip' length 152917 bytes (149 KB)
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downloaded 149 KB

trying URL 'https://cloud.r-project.org/src/contrib/assertthat_0.2.1.tar.gz'
Content type 'application/x-gzip' length 12742 bytes (12 KB)
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downloaded 12 KB

trying URL 'https://cloud.r-project.org/src/contrib/cli_1.1.0.tar.gz'
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downloaded 39 KB

trying URL 'https://cloud.r-project.org/src/contrib/rlang_0.3.4.tar.gz'
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trying URL 'https://cloud.r-project.org/src/contrib/pls_2.7-1.tar.gz'
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downloaded 4.2 MB

trying URL 'https://cloud.r-project.org/src/contrib/testthat_2.0.1.tar.gz'
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downloaded 211 KB

trying URL 'https://cloud.r-project.org/src/contrib/apercu_0.2.3.tar.gz'
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downloaded 7010 bytes

* installing *source* package ‘assertthat’ ...
** package ‘assertthat’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (assertthat)
* installing *source* package ‘rlang’ ...
** package ‘rlang’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I./lib/  -I/usr/local/include  -fPIC  -Wall -g -O2  -c capture.c -o capture.o
clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I./lib/  -I/usr/local/include  -fPIC  -Wall -g -O2  -c export.c -o export.o
clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I./lib/  -I/usr/local/include  -fPIC  -Wall -g -O2  -c internal.c -o internal.o
clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I./lib/  -I/usr/local/include  -fPIC  -Wall -g -O2  -c lib.c -o lib.o
clang -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module -multiply_defined suppress -L/Library/Frameworks/R.framework/Resources/lib -L/usr/local/lib -o rlang.so capture.o export.o internal.o lib.o -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
installing to /private/var/folders/xn/m8dzdsgs7sg8q7jgflnqm8w80000gn/T/RtmphXMbzT/folder1/00LOCK-rlang/00new/rlang/libs
generating debug symbols (dSYM)
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
*** copying figures
** building package indices
** testing if installed package can be loaded from temporary location
** checking absolute paths in shared objects and dynamic libraries
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (rlang)
* installing *source* package ‘pls’ ...
** package ‘pls’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** data
*** moving datasets to lazyload DB
** inst
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** installing vignettes
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (pls)
* installing *source* package ‘cli’ ...
** package ‘cli’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** inst
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (cli)
* installing *source* package ‘apercu’ ...
** package ‘apercu’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (apercu)
* installing *source* package ‘testthat’ ...
** package ‘testthat’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/usr/local/include  -fPIC  -Wall -g -O2  -c init.c -o init.o
clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/usr/local/include  -fPIC  -Wall -g -O2  -c reassign.c -o reassign.o
clang++ -std=gnu++11 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/usr/local/include  -fPIC  -Wall -g -O2  -c test-catch.cpp -o test-catch.o
clang++ -std=gnu++11 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/usr/local/include  -fPIC  -Wall -g -O2  -c test-example.cpp -o test-example.o
clang++ -std=gnu++11 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I../inst/include -DCOMPILING_TESTTHAT  -I/usr/local/include  -fPIC  -Wall -g -O2  -c test-runner.cpp -o test-runner.o
clang++ -std=gnu++11 -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module -multiply_defined suppress -L/Library/Frameworks/R.framework/Resources/lib -L/usr/local/lib -o testthat.so init.o reassign.o test-catch.o test-example.o test-runner.o -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
installing to /private/var/folders/xn/m8dzdsgs7sg8q7jgflnqm8w80000gn/T/RtmphXMbzT/folder1/00LOCK-testthat/00new/testthat/libs
generating debug symbols (dSYM)
** R
** inst
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
*** copying figures
** building package indices
** installing vignettes
** testing if installed package can be loaded from temporary location
** checking absolute paths in shared objects and dynamic libraries
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (testthat)

The downloaded source packages are in
	'/private/var/folders/xn/m8dzdsgs7sg8q7jgflnqm8w80000gn/T/RtmphXMbzT/downloaded_packages'
* installing *source* package ‘dummyPackage’ ...
** using staged installation
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (dummyPackage)
trying URL 'https://cloud.r-project.org/src/contrib/apercu_0.2.3.tar.gz'
Content type 'application/x-gzip' length 7010 bytes
==================================================
downloaded 7010 bytes

* installing *source* package ‘apercu’ ...
** package ‘apercu’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (apercu)

The downloaded source packages are in
	'/private/var/folders/xn/m8dzdsgs7sg8q7jgflnqm8w80000gn/T/RtmphXMbzT/downloaded_packages'
trying URL 'https://cloud.r-project.org/src/contrib/apercu_0.2.3.tar.gz'
Content type 'application/x-gzip' length 7010 bytes
==================================================
downloaded 7010 bytes

* installing *source* package ‘apercu’ ...
** package ‘apercu’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (apercu)

The downloaded source packages are in
	'/private/var/folders/xn/m8dzdsgs7sg8q7jgflnqm8w80000gn/T/RtmphXMbzT/downloaded_packages'
trying URL 'https://cloud.r-project.org/src/contrib/apercu_0.2.3.tar.gz'
Content type 'application/x-gzip' length 7010 bytes
==================================================
downloaded 7010 bytes

* installing *source* package ‘apercu’ ...
** package ‘apercu’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation path
* DONE (apercu)

The downloaded source packages are in
	'/private/var/folders/xn/m8dzdsgs7sg8q7jgflnqm8w80000gn/T/RtmphXMbzT/downloaded_packages'
Error: processing vignette 'help.Rmd' failed with diagnostics:
there is no package called ‘markdown’
--- failed re-building ‘help.Rmd’

SUMMARY: processing the following file failed:
  ‘help.Rmd’

Error: Vignette re-building failed.
Execution halted