Add pre-release notes ci job

[ZLLentz]

Some of our Python packages require the user to add some release notes to each PR

There must be some way we can enshrine this in ci

• Fail if there's no release notes file?
• Fail if a release notes file is added, but it doesn't have any contributors?
• Fail if the contributors list doesn't include the user's github username?

[tangkong]

I think it shouldn't go in pre-commit hooks, since we probably can't / shouldn't require pre-release notes to exist at every commit at every point in the branch.

A small ci helper job seems like the right place for this though.

Now as for the actual checking of github usernames etc, that's another problem to be solved. Maybe this can also attempt to validate the rst or something? (I guess formatting will just look ugly but not error, most of the time)

[ZLLentz]

Moved from pre commit repo to ci helpers repo and changed the wording to match