build(deps): bump prost-types from 0.12.3 to 0.12.4 (#332)

Bumps [prost-types](https://github.com/tokio-rs/prost) from 0.12.3 to 0.12.4.
- [Release notes](https://github.com/tokio-rs/prost/releases)
- [Commits](tokio-rs/prost@v0.12.3...v0.12.4)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.lock

@@ -429,9 +429,9 @@ dependencies = [
 
 [[package]]
 name = "prost-types"
-version = "0.12.3"
+version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "193898f59edcf43c26227dcd4c8427f00d99d61e95dcde58dabd49fa291d470e"
+checksum = "3235c33eb02c1f1e212abdbe34c78b264b038fb58ca612664343271e36e55ffe"
 dependencies = [
  "prost",
 ]