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/contrib/4.0/ps_1.3.3.tgz'
Content type 'application/x-gzip' length 218263 bytes (213 KB)
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downloaded 213 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/processx_3.4.3.tgz'
Content type 'application/x-gzip' length 278450 bytes (271 KB)
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downloaded 271 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/callr_3.4.3.tgz'
Content type 'application/x-gzip' length 385702 bytes (376 KB)
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downloaded 376 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/prettyunits_1.1.1.tgz'
Content type 'application/x-gzip' length 34704 bytes (33 KB)
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downloaded 33 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/backports_1.1.8.tgz'
Content type 'application/x-gzip' length 71654 bytes (69 KB)
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downloaded 69 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/assertthat_0.2.1.tgz'
Content type 'application/x-gzip' length 52572 bytes (51 KB)
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downloaded 51 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/glue_1.4.1.tgz'
Content type 'application/x-gzip' length 138294 bytes (135 KB)
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downloaded 135 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/fansi_0.4.1.tgz'
Content type 'application/x-gzip' length 210700 bytes (205 KB)
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downloaded 205 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/desc_1.2.0.tgz'
Content type 'application/x-gzip' length 285234 bytes (278 KB)
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downloaded 278 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/rprojroot_1.3-2.tgz'
Content type 'application/x-gzip' length 79148 bytes (77 KB)
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downloaded 77 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/rstudioapi_0.11.tgz'
Content type 'application/x-gzip' length 257646 bytes (251 KB)
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downloaded 251 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/cli_2.0.2.tgz'
Content type 'application/x-gzip' length 395495 bytes (386 KB)
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downloaded 386 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/crayon_1.3.4.tgz'
Content type 'application/x-gzip' length 748897 bytes (731 KB)
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downloaded 731 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/digest_0.6.25.tgz'
Content type 'application/x-gzip' length 246065 bytes (240 KB)
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downloaded 240 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/ellipsis_0.3.1.tgz'
Content type 'application/x-gzip' length 33497 bytes (32 KB)
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downloaded 32 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/evaluate_0.14.tgz'
Content type 'application/x-gzip' length 74355 bytes (72 KB)
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downloaded 72 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/magrittr_1.5.tgz'
Content type 'application/x-gzip' length 153226 bytes (149 KB)
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downloaded 149 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/pkgload_1.1.0.tgz'
Content type 'application/x-gzip' length 152111 bytes (148 KB)
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downloaded 148 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/praise_1.0.0.tgz'
Content type 'application/x-gzip' length 16137 bytes (15 KB)
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downloaded 15 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/R6_2.4.1.tgz'
Content type 'application/x-gzip' length 57553 bytes (56 KB)
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downloaded 56 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/withr_2.2.0.tgz'
Content type 'application/x-gzip' length 205737 bytes (200 KB)
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downloaded 200 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/pls_2.7-2.tgz'
Content type 'application/x-gzip' length 1228765 bytes (1.2 MB)
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downloaded 1.2 MB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/testthat_2.3.2.tgz'
Content type 'application/x-gzip' length 2377186 bytes (2.3 MB)
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downloaded 2.3 MB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/apercu_0.2.4.tgz'
Content type 'application/x-gzip' length 26070 bytes (25 KB)
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downloaded 25 KB

trying URL 'https://cloud.r-project.org/src/contrib/pkgbuild_1.1.0.tar.gz'
Content type 'application/x-gzip' length 29854 bytes (29 KB)
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downloaded 29 KB

trying URL 'https://cloud.r-project.org/src/contrib/rlang_0.4.7.tar.gz'
Content type 'application/x-gzip' length 847308 bytes (827 KB)
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downloaded 827 KB

* installing *source* package ‘pkgbuild’ ...
** package ‘pkgbuild’ 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 (pkgbuild)
* installing *source* package ‘rlang’ ...
** package ‘rlang’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
clang -mmacosx-version-min=10.13 -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 -mmacosx-version-min=10.13 -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 -mmacosx-version-min=10.13 -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 -mmacosx-version-min=10.13 -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 -mmacosx-version-min=10.13 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -I./lib/  -I/usr/local/include   -fPIC  -Wall -g -O2  -c version.c -o version.o
clang -mmacosx-version-min=10.13 -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 version.o -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
installing to /Volumes/Temp/tmp/RtmpCQKXyp/folder1/00LOCK-rlang/00new/rlang/libs
** generating debug symbols (dSYM)
** R
** inst
** 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)

The downloaded source packages are in
	'/Volumes/Temp/tmp/RtmpCQKXyp/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/bin/macosx/contrib/4.0/apercu_0.2.4.tgz'
Content type 'application/x-gzip' length 26070 bytes (25 KB)
==================================================
downloaded 25 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/apercu_0.2.4.tgz'
Content type 'application/x-gzip' length 26070 bytes (25 KB)
==================================================
downloaded 25 KB

trying URL 'https://cloud.r-project.org/bin/macosx/contrib/4.0/apercu_0.2.4.tgz'
Content type 'application/x-gzip' length 26070 bytes (25 KB)
==================================================
downloaded 25 KB

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