build(deps): update prost-types requirement from 0.12.0 to 0.13.1

Updates the requirements on [prost-types](https://github.com/tokio-rs/prost) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/prost/releases)
- [Changelog](https://github.com/tokio-rs/prost/blob/master/CHANGELOG.md)
- [Commits](tokio-rs/prost@v0.12.0...v0.13.1)

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

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

Author: dependabot[bot]

Cargo.toml

@@ -23,7 +23,7 @@ itoa = "1.0"
 parking_lot = "0.12"
 prometheus-client-derive-encode = { version = "0.4.1", path = "derive-encode" }
 prost = { version = "0.12.0", optional = true }
-prost-types = { version = "0.12.0", optional = true }
+prost-types = { version = "0.13.1", optional = true }
 
 [dev-dependencies]
 async-std = { version = "1", features = ["attributes"] }