Bump version to 3.6.7
Bump version to 3.6.7

brianstien/protobuf,localshred/protobuf,quixoten/protobuf,quixoten/protobuf,lookout/protobuffy,ruby-protobuf/protobuf,brianstien/protobuf,localshred/protobuf,lookout/protobuffy,ruby-protobuf/protobuf