Update packaging to 20.0

[pyup-bot]

This PR updates packaging from 19.2 to 20.0.

Changelog

20.0

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

* Add type hints (:issue:`191`)

* Add proper trove classifiers for PyPy support (:issue:`198`)

* Scale back depending on ``ctypes`` for manylinux support detection (:issue:`171`)

* Use ``sys.implementation.name`` where appropriate for ``packaging.tags`` (:issue:`193`)

* Expand upon the API provded by ``packaging.tags``: ``interpreter_name()``, ``mac_platforms()``, ``compatible_tags()``, ``cpython_tags()``, ``generic_tags()`` (:issue:`187`)

* Officially support Python 3.8 (:issue:`232`)

* Add ``major``, ``minor``, and ``micro`` aliases to ``packaging.version.Version`` (:issue:`226`)

* Properly mark ``packaging`` has being fully typed by adding a `py.typed` file (:issue:`226`)

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 #206