Update packaging to 21.0

[pyup-bot]

This PR updates packaging from 20.8 to 21.0.

Changelog

21.0

~~~~~~~~~~~~~~~~~

* `packaging` is now only compatible with Python 3.6 and above.
* Add support for zip files in ``parse_sdist_filename`` (:issue:`429`)

20.9

~~~~~~~~~~~~~~~~~

* 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`)

Links

• PyPI: https://pypi.org/project/packaging
• Changelog: https://pyup.io/changelogs/packaging/
• Repo: https://github.com/pypa/packaging

[pyup-bot]

Closing this in favor of #118