loongson/mirror: links for alerta-slack

loongson/mirror alerta-slack-0.3.3.tar.gz
loongson/mirror alerta-slack-0.3.1.tar.gz
loongson/mirror alerta-slack-0.1.4.tar.gz
loongson/mirror alerta-slack-0.1.3.tar.gz
loongson/mirror alerta-slack-0.1.2.tar.gz