Fix typos in README.md

#N/A: Fix a couple of issues after new flake8 release

#1329: Add support for Windows `CMD` and easier setup for Powershell

#1248: Use imp only when importlib.util not available

#1248: Skip a failing test when running on Windows

#1248: Check for multiple patterns in functional tests

#1248: Check container status before test functions

#1248: Reuse Docker images in functional tests

#1248: Move deprecated Python versions to separate workflow job

#1248: Run workflows on push and pull_request

Add support for Python 3.11

Add python_requires to help pip

Update min Python 3 version required in README

Drop the dot https://twitter.com/pytestdotorg/status/753767547866972160

Test on Python 3.10 final