loongson/mirror: links for burttraver

loongson/mirror burttraver-0.3.0.tar.gz
loongson/mirror burttraver-0.3.0-py3-none-any.whl
loongson/mirror burttraver-0.2.0.tar.gz
loongson/mirror burttraver-0.2.0-py3-none-any.whl