Bump @tiptap/starter-kit from 2.6.6 to 2.9.1

Bumps [@tiptap/starter-kit](https://github.com/ueberdosis/tiptap/tree/HEAD/packages/starter-kit) from 2.6.6 to 2.9.1.
- [Release notes](https://github.com/ueberdosis/tiptap/releases)
- [Changelog](https://github.com/ueberdosis/tiptap/blob/develop/packages/starter-kit/CHANGELOG.md)
- [Commits](https://github.com/ueberdosis/tiptap/commits/@tiptap/[email protected]/packages/starter-kit)

---
updated-dependencies:
- dependency-name: "@tiptap/starter-kit"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>