This adds official support for the upcoming Python 3.11 release in October (unless it gets delayed - RC2 already is).

Python 3.11 deprecations in the stdlib have already been fixed:

• cli: refactor nested argparse argument groups #4651
• utils.l10n: switch to locale.getlocale() #4654

and dependency-wise, I haven't noticed any problems apart from lxml still only having released pre-built cp311 wheels for musllinux_1_1, manylinux_2014_x86_64 and manylinux_2010_i686, so other platforms will have to build from source with libxml2 and libxslt being installed, but that will get resolved hopefully soon:

• https://pypi.org/project/lxml/4.9.1/#files
• https://bugs.launchpad.net/lxml/+bug/1977998