loongson/pypi: links for python-dateutil

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

loongson/pypi python_dateutil-2.8.2-py2.py3-none-any.whl
loongson/pypi python_dateutil-2.8.1-py2.py3-none-any.whl
loongson/pypi python_dateutil-2.7.5-py2.py3-none-any.whl