Upload only out folder as artifact, which is the actual PSSA artifact

[bergmeister]

PR Summary

As per title, at the moment, we upload the full repo, which is not necessary, just the out folder is enough
Related #622
Should we document this and give details which build to choose (since all builds build only for their specific PowerShell version) and tell having to unblock the zip?
To fully close the issue we would need to change one of the build jobs to build for all PowerShell versions.
WDYT?

PR Checklist

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[JamesWTruher]

LGTM