The Contributor Map workflow fails

[Piedone]

Describe the bug

The Contributor Map action fails because it can't push to the main branch due to its branch protection rules.

To Reproduce

This fails every time if the workflow is run, what happens every Monday.

Expected behavior

The upgraded contributor map is committed to the repo. However, since GHA doesn't support adding an exception for such a workflow, this won't work. So, we can switch this to on-demand execution and occasionally open PRs to update it.

We could also make the workflow open PRs automatically.

[Piedone]

FYI why we get Node deprecation warnings: tunaitis/contributor-map#9