GHSA-6h2f-c8jm-84hc: Gitea archived repository release, milestone and label modification

The API routes for releases, release assets, milestones and repository labels did not reject changes to archived repositories. A user with write access to an archived repository, or a holder of such a user's write-scoped token, could replace or delete release assets while keeping their download URLs, delete releases and tags, and create, edit or delete milestones and labels of a repository that is meant to be read-only. Changing requests on these routes now return 423 Locked for archived repositories.