loongson/pypi: links for scratch-ext

loongson/mirror scratch-ext-0.7.6.tar.gz
loongson/mirror scratch-ext-0.7.5.tar.gz
loongson/mirror scratch-ext-0.6.1.tar.gz
loongson/mirror scratch-ext-0.5.5.tar.gz
loongson/mirror scratch-ext-0.5.4.tar.gz
loongson/mirror scratch-ext-0.5.3.tar.gz
loongson/mirror scratch-ext-0.5.2.tar.gz