Better release automation?

[sourcefrog]

• [ ] Upload to crates.io from an action triggered by a new release?
• [ ] Autogenerate changelog, maybe using git-cliff?
• [ ] Look at release-plz or similar tools? (Will they support calver?)
• [ ] Put the recent changelog into the GitHub release announcement, while preferably also still auto-building binaries?
• [ ] Create an announcement thread for releases? (Worth it?)
• [ ] Enable auto-merge on PRs? (Maybe requires different branch protection rules to tell it when merges should be allowed?)
• [ ] Auto-create signed tags somehow?