community/py3-protobuf: drop dependency on py3-six
not needed since 2021 / 3.19.0: https://github.com/protocolbuffers/protobuf/commit/f8a22b45c041 https://github.com/protocolbuffers/protobuf/commit/a33aa736fc71
not needed since 2021 / 3.19.0: https://github.com/protocolbuffers/protobuf/commit/f8a22b45c041 https://github.com/protocolbuffers/protobuf/commit/a33aa736fc71