Bump dulwich from 0.20.50 to 0.22.1

Bumps [dulwich](https://github.com/dulwich/dulwich) from 0.20.50 to 0.22.1.
- [Release notes](https://github.com/dulwich/dulwich/releases)
- [Changelog](https://github.com/jelmer/dulwich/blob/master/NEWS)
- [Commits](https://github.com/dulwich/dulwich/compare/dulwich-0.20.50...dulwich-0.22.1

)

---
updated-dependencies:
- dependency-name: dulwich
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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