loongson/pypi: links for pcnnlib

loongson/mirror PcnnLib-0.7.tar.gz
loongson/mirror PcnnLib-0.6.tar.gz
loongson/mirror PcnnLib-0.5.tar.gz
loongson/mirror PcnnLib-0.4.tar.gz
loongson/mirror PcnnLib-0.3.tar.gz