loongson/pypi: links for singledispatch

INFO: Because this project isn't in the mirror_whitelist, no releases from root/pypi are included.

loongson/pypi singledispatch-3.7.0-py2.py3-none-any.whl
loongson/pypi singledispatch-3.4.0.3-py3-none-any.whl
loongson/pypi singledispatch-3.4.0.3-py2-none-any.whl