Error(s) in re-building vignettes:
  ...
--- re-building ‘Package-usage.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Warning in in_dir(input_dir(), evaluate(code, envir = env, new_device = FALSE,  :
  You changed the working directory to /home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes/concatipede_test (probably via setwd()). It will be restored to /home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes. See the Note section in ?knitr::knit
── Attaching packages ──────────────────────────────────────────── tidyverse 1.3.1 ──
✔ ggplot2 3.3.5     ✔ purrr   0.3.4
✔ tibble  3.1.3     ✔ dplyr   1.0.7
✔ tidyr   1.1.3     ✔ stringr 1.4.0
✔ readr   2.0.1     ✔ forcats 0.5.1
── Conflicts ─────────────────────────────────────────────── tidyverse_conflicts() ──
✖ dplyr::filter() masks stats::filter()
✖ dplyr::lag()    masks stats::lag()
Loading the fasta files from the current directory (/home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes).
Loading the fasta files from the current directory (/home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes).
Loading the fasta files from the current directory (/home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes).
Loading the fasta files from the current directory (/home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes).
Loading the fasta files from the current directory (/home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes).
Loading the fasta files from the current directory (/home/ripley/R/packages/tests32/concatipede.Rcheck/vign_test/concatipede/vignettes).
Quitting from lines 146-153 (Package-usage.Rmd) 
Error: processing vignette 'Package-usage.Rmd' failed with diagnostics:
there is no package called 'webshot'
--- failed re-building ‘Package-usage.Rmd’

SUMMARY: processing the following file failed:
  ‘Package-usage.Rmd’

Error: Vignette re-building failed.
Execution halted