Fix Readme `pub get` instead of `pub install`. (#486)
Fix Readme `pub get` instead of `pub install`. (#486)

Co-authored-by: Ömer Sinan Ağacan <d15e39adaef0c3a64e4ea5d68f5c1b5be1f04e29@google.com>
google/protobuf.dart,dart-lang/dart-protobuf,dart-lang/protobuf,google/protobuf.dart,dart-lang/dart-protobuf,dart-lang/protobuf,dart-lang/dart-protobuf,google/protobuf.dart,dart-lang/protobuf