Update whitenoise to 6.4.0

[pyup-bot]

This PR updates whitenoise from 6.3.0 to 6.4.0.

Changelog

6.4.0

------------------

* Support Django 4.2.

* Remove further support for byte strings from the ``root`` and ``prefix`` arguments to ``WhiteNoise``, and Django’s ``STATIC_ROOT`` setting.
Like in the previous release, this seems to be a remnant of Python 2 support.
Again, this change may be backwards incompatible for a small number of projects, but it’s unlikely.
Django does not support ``STATIC_ROOT`` being a byte string.

Links

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

[pyup-bot]

Closing this in favor of #151