fix(dependabot): bump @contentful/rich-text-types from 16.6.1 to 16.8.3

Bumps [@contentful/rich-text-types](https://github.com/contentful/rich-text) from 16.6.1 to 16.8.3.
- [Release notes](https://github.com/contentful/rich-text/releases)
- [Changelog](https://github.com/contentful/rich-text/blob/master/CHANGELOG.md)
- [Commits](https://github.com/contentful/rich-text/compare/@contentful/rich-text-types@16.6.1...@contentful/rich-text-types@16.8.3)

---
updated-dependencies:
- dependency-name: "@contentful/rich-text-types"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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