Allow changelog generation on any protected branch

With a main/dev/release branch strategy, as commits are cherry-picked from release to dev, and from dev to main, they will appear on different branches with different SHAs.

Allow the Changelog to be regenerated on any protected branch (not just the release branch), so that the history is always accurate for that branch.

It follows from this that updates to the Changelog should never be cherry-picked from one protected branch to another.