loongson/pypi: links for dubbo-client

loongson/mirror dubbo-client-1.0.0b5.tar.gz
loongson/mirror dubbo-client-1.0.0b4.tar.gz
loongson/mirror dubbo-client-1.0.0b3.tar.gz
loongson/mirror dubbo-client-1.0.0b2.tar.gz