Using $GITHUB_WORKSPACE for base dir

[caic99]

Probably fix #23 .

[platisd]

Cool, do you have a run where this has worked without issues?

[oleg-derevenetz]

Just like I said, this will not work. This is the result of performing this action with the change you suggest for test PR:

https://github.com/oleg-derevenetz/fheroes2/runs/6074036612?check_suite_focus=true

please note that the printed value of GITHUB_WORKSPACE is wrong. This is the result of performing the original action with the same set of changes:

https://github.com/oleg-derevenetz/fheroes2/runs/6074169583?check_suite_focus=true

Please note that in the second case the corresponding warning was added to the PR:

oleg-derevenetz/fheroes2#76 (review)

[caic99]

@oleg-derevenetz You are right, and thanks a lot for your test. I think this idea using GitHub env vars won't work, for it does not contain info between steps.
What do you guys think about setting '/home/runner/work/' as a parameter? For people using containers, just pass '/__w/' is OK.