LICENSE file is missing in 20.5 pypi release

[priv-kweihmann]

# cat packaging/__init__.py
# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.

but named file is not shipped with packaging-20.5.tar.gz.
That was different for 20.4 releases

[pradyunsg]

Oooo. Nice catch!

We're probably want to add this in using flit's sdist section: https://flit.readthedocs.io/en/stable/pyproject_toml.html#sdist-section. PRs welcome! ^>^