loongson/pypi: links for umysql-2018

loongson/mirror umysql-2018-2.63.7.tar.gz
loongson/mirror umysql-2018-2.63.4.tar.gz
loongson/mirror umysql-2018-2.63.3.tar.gz
loongson/mirror umysql-2018-2.63.2.tar.gz