build(deps): update prost-build requirement from 0.11.0 to 0.12.1

Updates the requirements on [prost-build](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...v0.12.1)

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

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

Cargo.toml

@@ -38,7 +38,7 @@ tokio = { version = "1", features = ["rt-multi-thread", "net", "macros", "signal
 hyper = { version = "0.14.16", features = ["server", "http1", "tcp"] }
 
 [build-dependencies]
-prost-build = { version = "0.11.0", optional = true }
+prost-build = { version = "0.12.1", optional = true }
 
 [[bench]]
 name = "family"