loongson/pypi: links for imgtests

loongson/mirror imgtests-2.5.tar.gz
loongson/mirror imgtests-2.4.tar.gz
loongson/mirror imgtests-2.3.tar.gz
loongson/mirror imgtests-2.2.tar.gz
loongson/mirror imgtests-2.1.tar.gz
loongson/mirror imgtests-2.tar.gz