Add Python 3.11 support

[ReubenJ]

Currently, 3.11 is not listed as supported. This PR adds 3.11 to the testing matrix and updates the relevant classifier in setup.py.

Motivation

My apologies, this might be a mess to read, and is probably irrelevant for most readers.

This is part of an attempt to fix installs for snakemake/snakemake >7.x on linux ARM. One of snakemake's dependencies, yte, is blocking this by not supporting linux ARM. In the process of updating yte, I realized that when migrating from 1.x to 2.x, dpath dropped noarch support. I believe the lack of that support is blocking yte's support as well.

As such, I'd like to update the dpath-feedstock to ship a noarch version. Part of that process requires a constraint to be placed on dpaths's compatible python versions (conda-forge/dpath-feedstock#44). In the interest of making that version constraint as flexible as possible, I'd like to add 3.11 support. tox appears to pass all tests in 3.11, so I believe adding support is as simple as adding 3.11 to the testing matrix/updating the pypi badge.

[moomoohk]

Thanks Reuben.
Please bump the minor version so the change to setup.py will be pushed to PyPI.

[ReubenJ]

Sure—done! Looks like the tag will be handled by the deployment workflow, so the change to version.py is all that's needed, right?