loongson/pypi: links for xor-string

loongson/mirror xor_string-0.2.3.tar.gz
loongson/mirror xor_string-0.2.2.tar.gz
loongson/mirror xor_string-0.2.0.tar.gz
loongson/mirror xor_string-0.1.7.tar.gz
loongson/mirror xor_string-0.1.6.tar.gz