GeezerVison

Description:
There was a request to add non-zero exit in case if python-version input set to zero value, but @dmitry-shibanov warned it might break the existing builds.

I suggest to add a warning to the log instead of of non-zero exit code.

There's a build confirming no tool-cache python installed if python-version is empty.

Related issue:
related issue.

Check list:

• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.