Log Message:
py-packaging: update to 20.8.

20.8 - 2020-12-11
~~~~~~~~~~~~~~~~~

* Revert back to setuptools for compatibility purposes for some Linux distros \ 
(:issue:`363`)
* Do not insert an underscore in wheel tags when the interpreter version number
  is more than 2 digits (:issue:`372`)

20.7 - 2020-11-28
~~~~~~~~~~~~~~~~~

No unreleased changes.

20.6 - 2020-11-28
~~~~~~~~~~~~~~~~~

.. note:: This release was subsequently yanked, and these changes were included \ 
in 20.7.

* Fix flit configuration, to include LICENSE files (:issue:`357`)
* Make `intel` a recognized CPU architecture for the `universal` macOS platform \ 
tag (:issue:`361`)
* Add some missing type hints to `packaging.requirements` (issue:`350`)

20.5 - 2020-11-27
~~~~~~~~~~~~~~~~~

* Officially support Python 3.9 (:issue:`343`)
* Deprecate the ``LegacyVersion`` and ``LegacySpecifier`` classes (:issue:`321`)
* Handle ``OSError`` on non-dynamic executables when attempting to resolve
  the glibc version string.