chore: Bump prost from 0.12.1 to 0.12.2

Bumps [prost](https://github.com/tokio-rs/prost) from 0.12.1 to 0.12.2.
- [Release notes](https://github.com/tokio-rs/prost/releases)
- [Commits](tokio-rs/prost@v0.12.1...v0.12.2)

---
updated-dependencies:
- dependency-name: prost
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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