Error(s) in re-building vignettes:
  ...
--- re-building ‘apexcharter.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.

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union

Quitting from lines 37-41 (apexcharter.Rmd) 
Error: processing vignette 'apexcharter.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘apexcharter.Rmd’

--- re-building ‘labs.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.

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union

Quitting from lines 32-34 (labs.Rmd) 
Error: processing vignette 'labs.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘labs.Rmd’

--- re-building ‘lines.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.

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union

Quitting from lines 39-40 (lines.Rmd) 
Error: processing vignette 'lines.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘lines.Rmd’

--- re-building ‘shiny-integration.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.
Quitting from lines 91-98 (shiny-integration.Rmd) 
Error: processing vignette 'shiny-integration.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘shiny-integration.Rmd’

--- re-building ‘sync-charts.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.
Quitting from lines 59-60 (sync-charts.Rmd) 
Error: processing vignette 'sync-charts.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘sync-charts.Rmd’

SUMMARY: processing the following files failed:
  ‘apexcharter.Rmd’ ‘labs.Rmd’ ‘lines.Rmd’ ‘shiny-integration.Rmd’
  ‘sync-charts.Rmd’

Error: Vignette re-building failed.
Execution halted