loongson/pypi: links for blackbench

loongson/mirror blackbench-21.8a2.tar.gz
loongson/mirror blackbench-21.8a2-py3-none-any.whl
loongson/mirror blackbench-21.8a1.tar.gz
loongson/mirror blackbench-21.8a1-py3-none-any.whl