loongson/mirror: links for sievemgr

loongson/mirror sievemgr-0.7.4.7.tar.gz
loongson/mirror sievemgr-0.7.4.7-py3-none-any.whl
loongson/mirror sievemgr-0.7.4.6.tar.gz
loongson/mirror sievemgr-0.7.4.6-py3-none-any.whl