Update prost requirement from 0.11 to 0.12

Updates the requirements on [prost](https://github.com/tokio-rs/prost) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/prost/releases)
- [Commits](tokio-rs/prost@prost-build-0.11.1...v0.12.0)

---
updated-dependencies:
- dependency-name: prost
  dependency-type: direct:production
...

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

Cargo.toml

@@ -16,7 +16,7 @@ tls = ["tokio-rustls", "webpki-roots"]
 tokio = { version = "1.0", features = ["rt", "net"] }
 tokio-util = { version = "0.7", features = ["codec"] }
 futures = "0.3.6"
-prost = "0.11"
+prost = "0.12"
 derive_builder = "0.12"
 getset = "0.1.1"
 thiserror = "1"