Bump mkdocstrings from 0.21.2 to 0.22.0

Bumps [mkdocstrings](https://github.com/mkdocstrings/mkdocstrings) from 0.21.2 to 0.22.0.
- [Release notes](https://github.com/mkdocstrings/mkdocstrings/releases)
- [Changelog](https://github.com/mkdocstrings/mkdocstrings/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mkdocstrings/mkdocstrings/compare/0.21.2...0.22.0)

---
updated-dependencies:
- dependency-name: mkdocstrings
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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