passing the actual path of Polaris to GITHUB_PATH

[michaelniemand]

I don't understand how this could have ever worked before, just passing "polaris" to GITHUB_PATH before, not the actual, absolute path?!

This PR fixes #

Checklist

• [x] I have signed the CLA
• [ ] I have updated/added any relevant documentation

Description

What's the goal of this PR?

the install script does not work, the polaris executable is not found

What changes did you make?

passing the actual path to the executable to GITHUB_PATH

What alternative solution should we consider, if any?

[CLAassistant]

All committers have signed the CLA.