loongson/pypi: links for petgem

loongson/mirror petgem-0.9.tar.gz
loongson/mirror petgem-0.8.tar.gz
loongson/mirror petgem-0.7.tar.gz
loongson/mirror petgem-0.6.tar.gz
loongson/mirror petgem-0.5.tar.gz
loongson/mirror petgem-0.4.tar.gz