Add support for a custom commit message when cherry-picking commits using the API

Merged Yorick Peterse requested to merge cherry-pick-custom-commit-message into master

What does this MR do?

This adds support for specifying a custom commit message when cherry-picking a commit using the API.

This is needed to resolve release-tools#500 (closed), as Release Tools needs a way to cherry-pick commits while retaining the Git trailers we use for generating changelogs.

Does this MR meet the acceptance criteria?

Conformity

Edited by Yorick Peterse