Error(s) in re-building vignettes:
--- re-building ‘basics.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'basics.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘basics.Rmd’

--- re-building ‘docker.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'docker.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘docker.Rmd’

--- re-building ‘headless.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'headless.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘headless.Rmd’

--- re-building ‘internetexplorer.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'internetexplorer.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘internetexplorer.Rmd’

--- re-building ‘saucelabs.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'saucelabs.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘saucelabs.Rmd’

--- re-building ‘shinytesting.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'shinytesting.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘shinytesting.Rmd’

--- re-building ‘webinar.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'webinar.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘webinar.Rmd’

SUMMARY: processing the following files failed:
  ‘basics.Rmd’ ‘docker.Rmd’ ‘headless.Rmd’ ‘internetexplorer.Rmd’
  ‘saucelabs.Rmd’ ‘shinytesting.Rmd’ ‘webinar.Rmd’

Error: Vignette re-building failed.
Execution halted