fix: docs github mirror action

[ludamad]

Description

Should fix master.

The action had failed in master asking for identity. As well, I noticed that if the subrepo is updated, and then a commit squashed, the parent might become not a real commit. I kludged a fix for a squash workflow by finding the parent commit of where the file was edited last.

Checklist:

• [*] I have reviewed my diff in github, line by line.
• [*] Every change is related to the PR description.
• [*] I have linked this pull request to the issue(s) that it resolves.
• [*] There are no unexpected formatting changes, superfluous debug logs, or commented-out code.
• [*] The branch has been merged or rebased against the head of its merge target.
• [*] I'm happy for the PR to be merged at the reviewer's next convenience.

[dbanks12]

LGTM

[dbanks12]

Very nice