how to add non failing lintr checks in tic.R

Question

I would like to add non failing lintr checks to my (TravisCI-based) CI via tic.

(Initially I implemented the testthat approach but it is too bothersome for development.)

The lintr documentation provides an example for .travis.yml

after_success:
  - R CMD INSTALL $PKG_TARBALL
  - Rscript -e 'lintr::lint_package()'

Which I (naively) implemented in my tic.R as

# run lintr after successful CI build
get_stage("after_success") %>%
  add_code_step(lintr::lint_package())

but this is NOT working and lintr-bot is not commenting on my PR unlike it was with the testthat approach.

I guess the problem is in the missing implementation in tic.R of

  - R CMD INSTALL $PKG_TARBALL

I have no idea about how to do that if it is indeed the issue, so any hints/helps is highly appreciated and welcome!