Log Message:
py-packaging: update to 20.9.

20.9 - 2021-01-29
~~~~~~~~~~~~~~~~~

* Run [isort](https://pypi.org/project/isort/) over the code base (:issue:`377`)
* Add support for the ``macosx_10_*_universal2`` platform tags (:issue:`379`)
* Introduce ``packaging.utils.parse_wheel_filename()`` and ``parse_sdist_filename()``
  (:issue:`387` and :issue:`389`)