fix: remove unecessary dependencies in vignettes (readr and lubridate)

- Change format from tab separator to ";" separator in provided files because empty cells are removed if trailing spaces are deleted by the text editor

Refs #14
2 jobs for airGRbranch in 14 minutes and 34 seconds (queued for 1 second)
Status Name Job ID Coverage
  Checks
failed check_as_cran #137487
docker

00:14:34

failed check_not_cran #137486
docker

00:14:30

 
Name Stage Failure
failed
check_as_cran Checks
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> devtools::install_deps(dep = T)
Error in loadNamespace(name) : there is no package called ‘devtools’
Calls: :: ... loadNamespace -> withRestarts -> withOneRestart -> doWithOneRestart
Execution halted
Cleaning up file based variables
ERROR: Job failed: exit code 1
failed
check_not_cran Checks
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> devtools::install_deps(dep = T)
Error in loadNamespace(name) : there is no package called ‘devtools’
Calls: :: ... loadNamespace -> withRestarts -> withOneRestart -> doWithOneRestart
Execution halted
Cleaning up file based variables
ERROR: Job failed: exit code 1