Update tonic-build requirement from 0.11.0 to 0.12.0 in /hello-grpc-rust

Updates the requirements on [tonic-build](https://github.com/hyperium/tonic) to permit the latest version.
- [Release notes](https://github.com/hyperium/tonic/releases)
- [Changelog](https://github.com/hyperium/tonic/blob/master/CHANGELOG.md)
- [Commits](hyperium/tonic@v0.11.0...v0.12.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

hello-grpc-rust/Cargo.toml

@@ -51,4 +51,4 @@ once_cell = "1.18.0"
 
 [build-dependencies]
 #https://lib.rs/crates/tonic-build
-tonic-build = "0.11.0"
+tonic-build = "0.12.0"