Fix resolving check-dir when changing working-directory

[riccardoporreca]

• Should fix Upload of artifacts fails when working-directory is set for check-r-package #614, at least for the typical case where check-dir is a relative path.
• check-dir is now resolved relative to the working directory, as absolute path to also make it independent of the working directory of subsequent steps were the resolved check-dir-path output is used.

See run https://github.com/riccardoporreca/actions/runs/8194198667?check_suite_focus=true#step:6:169 reproducing the issue:

Warning: No files were found with the provided path: non-default-dir. No artifacts will be uploaded.

See the same case fixed when using proposed fix from the branch in run https://github.com/riccardoporreca/actions/runs/8194292727?check_suite_focus=true#step:6:155

Run actions/upload-artifact@main
with:
name: Linux-rrelease-results
path: /home/runner/work/actions/actions/test_pkg_subdir/non-default-dir
if-no-files-found: warn
[...]
With the provided path, there will be 54 files uploaded
Starting artifact upload

[codecov-commenter]

Codecov Report

Merging #615 (8de5221) into v2-branch (4abf43a) will not change coverage.
The diff coverage is n/a.

❗ Current head 8de5221 differs from pull request most recent head eded980. Consider uploading reports for the commit eded980 to get more accurate results

@@             Coverage Diff             @@
##           v2-branch      #615   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
===========================================
  Files              2         2           
  Lines             10        10           
===========================================
  Hits              10        10           

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[gaborcsardi]

Thanks much!

[github-actions]

This pull request has been automatically locked. If you believe you have found a related problem, please file a new issue and include a link to this pull request.