loongson/pypi: links for rdiffb

loongson/mirror rdiffb-0.5.0.tar.gz
loongson/mirror rdiffb-0.5.0-py3-none-any.whl
loongson/mirror rdiffb-0.4.0.tar.gz
loongson/mirror rdiffb-0.3.0.tar.gz
loongson/mirror rdiffb-0.2.0.tar.gz