Error(s) in re-building vignettes:
  ...
--- re-building ‘robin.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.
Loading required package: usethis
Downloading GitHub repo ValeriaPolicastro/robin@master
Skipping 1 packages not available: gprege
Installing package into '/tmp/RtmpcpaiPD/RLIBS_3b49420f340'
(as 'lib' is unspecified)
* installing *source* package ‘robin’ ...
** using staged installation
** R
** 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 (robin)
Loading required package: igraph

Attaching package: 'igraph'

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

    decompose, spectrum

The following object is masked from 'package:base':

    union

Loading required package: gprege
Loading required package: gptk
Loading required package: Matrix
Loading required package: fields
Loading required package: spam
Loading required package: dotCall64
Loading required package: grid
Spam version 2.3-0 (2019-09-13) is loaded.
Type 'help( Spam)' or 'demo( spam)' for a short introduction 
and overview of this package.
Help for individual functions is also obtained by adding the
suffix '.spam' to the function name, e.g. 'help( chol.spam)'.

Attaching package: 'spam'

The following object is masked from 'package:Matrix':

    det

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

    backsolve, forwardsolve

Loading required package: maps
See https://github.com/NCAR/Fields for
 an extensive vignette, other supplements and source code 
Quitting from lines 76-77 (robin.Rmd) 
Error: processing vignette 'robin.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘robin.Rmd’

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

Error: Vignette re-building failed.
Execution halted