loongson/pypi: links for protobuf-custom-build

loongson/mirror protobuf-custom-build-0.2.0.tar.gz
loongson/mirror protobuf_custom_build-0.2.0-py3-none-any.whl
loongson/mirror protobuf-custom-build-0.1.0.tar.gz
loongson/mirror protobuf_custom_build-0.1.0-py3-none-any.whl