Add a script that posts an update on each issue that was fixed in a release

For each issue that's fixed by a release, post a comment on that issue saying "Fixed in vX.Y.Z" w/ a link to the GH release notes.

Start by inspecting the repository's existing release scripts and how they identify issues fixed in a release. Implement the update flow so each fixed issue receives a comment containing the release version and a link to the GitHub release notes, then verify it without posting unintended comments.

Written by the indexing model from the issue text.