DeprecationWarning from pkg_resources on Python 3.10+

# I have * [x] Tested with the latest release * [x] Tested with the current master branch * [x] Searched for similar existing issues ## Expected behaviour pysolr can be imported without warnings ## Actual behaviour pysolr causes a deprecation warning from importing pkg_resources on Python 3.10+ ## Steps to reproduce the behaviour ``` $ python -W ::DeprecationWarning -c 'import pysolr' /venv/lib/python3.10/site-packages/pysolr.py:14: DeprecationWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html from pkg_resources import DistributionNotFound, get_distribution, parse_version ``` ## Configuration * Operating system version: Ubuntu 22.04 LTS * Search engine version: * Python version: Python 3.10.12 * pysolr version: `3.10.0b2`