Error(s) in re-building vignettes:
  ...
--- re-building ‘pct-international.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.
Warning in st_centroid.sf(zones) :
  st_centroid assumes attributes are constant over geometries of x
Warning in st_centroid.sfc(st_geometry(x), of_largest_polygon = of_largest_polygon) :
  st_centroid does not give correct centroids for longitude/latitude data
Quitting from lines 109-116 (pct-international.Rmd) 
Error: processing vignette 'pct-international.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘pct-international.Rmd’

--- re-building ‘pct.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 169-175 (pct.Rmd) 
Error: processing vignette 'pct.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘pct.Rmd’

--- re-building ‘pct_training.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

trying URL 'https://github.com/npct/pct-outputs-regional-R/raw/master/commute/msoa/west-yorkshire/z.Rds'
Content type 'application/octet-stream' length 162690 bytes (158 KB)
==================================================
downloaded 158 KB

Loading required package: sp
trying URL 'https://github.com/npct/pct-outputs-regional-R/raw/master/commute/msoa/west-yorkshire/l.Rds'
Content type 'application/octet-stream' length 2325924 bytes (2.2 MB)
==================================================
downloaded 2.2 MB

Quitting from lines 93-110 (pct_training.Rmd) 
Error: processing vignette 'pct_training.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘pct_training.Rmd’

SUMMARY: processing the following files failed:
  ‘pct-international.Rmd’ ‘pct.Rmd’ ‘pct_training.Rmd’

Error: Vignette re-building failed.
Execution halted