Add list of contributors to changelog/release notes

[silvester-pari]

It would be really nice to see the list of contributors for a new version, or at least the contributor of each change in the list (like GitHub automated release notes does).
We could wait for release-please to implement this natively, or we try adding our own action for that (see e.g. googleapis/release-please#292).

[unnoq]

+1

[silvester-pari]

Turns out, if you auto-generate release notes (by clicking "Generate release notes" button), this is added automatically by GitHub:

maybe this can be triggered from a github action as well.

[silvester-pari]

There appears to be an open PR which aims to achieve this: googleapis/release-please#1938