chore: remove pin for types-protobuf to support 3.14#2544

ohmayr wants to merge 1 commit intomaingoogleapis/gapic-generator-python:mainfrom

update-types-protobuf-in-mypy-noxgoogleapis/gapic-generator-python:update-types-protobuf-in-mypy-noxCopy head branch name to clipboard