loongson/pypi: links for vbet

loongson/mirror vbet-6.20.4.tar.gz
loongson/mirror vbet-6.20.4-py3-none-any.whl
loongson/mirror vbet-6.20.3.tar.gz
loongson/mirror vbet-6.20.3-py3-none-any.whl
loongson/mirror vbet-6.20.2.tar.gz
loongson/mirror vbet-6.20.2-py3-none-any.whl