prepare

Draft a release's changelog entry from the changes since the last tag: take the note each change declared, rule on the ones that declared none, and collate them into the section for the version being released. Use before tagging a release, when asked what changed since the last release, or as a step in a repository's own release procedure. Triggers on: prepare the release, release notes for x.y.z, changelog entry for the release, what changed since the last release.