Bump @tiptap/extension-highlight from 3.15.3 to 3.20.5

Bumps [@tiptap/extension-highlight](https://github.com/ueberdosis/tiptap/tree/HEAD/packages/extension-highlight) from 3.15.3 to 3.20.5.
- [Release notes](https://github.com/ueberdosis/tiptap/releases)
- [Changelog](https://github.com/ueberdosis/tiptap/blob/main/packages/extension-highlight/CHANGELOG.md)
- [Commits](https://github.com/ueberdosis/tiptap/commits/v3.20.5/packages/extension-highlight)

---
updated-dependencies:
- dependency-name: "@tiptap/extension-highlight"
  dependency-version: 3.20.5
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]