[Feature request] Support PR co-authoring when squashing via commit description

[smoya]

Using squash merging strategy ends up with only one commit being merged, being the author of it the person who created the PR.

This leads to lose authority of commits. All changes of such a PR will appear to be introduced by the person who created the PR.
In order to add co-authors to a commit, you need to add each of those as extra line in the description of the commit as mentioned in https://docs.github.com/en/pull-requests/committing-changes-to-your-project/creating-and-editing-commits/creating-a-commit-with-multiple-authors#creating-co-authored-commits-on-the-command-line.

It would be awesome if this action introduces support for this.

In the meantime, I made up a workaround by adding an extra step prior to this action. See asyncapi/.github#176