mail/py-authres: Move MASTER_SITES to CHEESESHOP

Using CHEESESHOP (PyPI) is recommended as the default
MASTER_SITES for Python packages where the distribution
files (sdist) are available there, unless there are
compelling reasons to use an alternative source such
as GitHub, for example if test, data or other important
files are not included due to incorrect packaging or otherwise.

PR: 220257
Reported by: koobs
Reviewed by: koobs, garga
Approved by: garga (mentor), yasu@utahime.org (maintainer)
Differential Revision: D11343