Migrate to the latest `protoc` once JS codegen is fixed

At the moment, `protoc` artifacts of `3.21.x` release branch [are known](https://github.com/protocolbuffers/protobuf-javascript/issues/127) to break the JS code generation. Therefore, the latest `3.20.3` is now forced for `time` library.

In scope of this issue we'll need to migrate back to the latest `protoc` artifact, once the corresponding Proto issue is addressed.