build(deps): bump prost-build from 0.12.4 to 0.12.6 (#170)

Bumps [prost-build](https://github.com/tokio-rs/prost) from 0.12.4 to 0.12.6.
- [Release notes](https://github.com/tokio-rs/prost/releases)
- [Commits](https://github.com/tokio-rs/prost/compare/v0.12.4...v0.12.6)

---
updated-dependencies:
- dependency-name: prost-build
  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

@@ -2169,9 +2169,9 @@ dependencies = [
 
 [[package]]
 name = "prost-build"
-version = "0.12.4"
+version = "0.12.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80b776a1b2dc779f5ee0641f8ade0125bc1298dd41a9a0c16d8bd57b42d222b1"
+checksum = "22505a5c94da8e3b7c2996394d1c933236c4d743e81a410bcca4e6989fc066a4"
 dependencies = [
  "bytes",
  "heck 0.5.0",