.circleci: Run python-package tests against Python 3.10 (Ubuntu 22.04)
.circleci: Run python-package tests against Python 3.10 (Ubuntu 22.04)

These "cimg/" docker images are CirceCI's new images:
https://circleci.com/developer/images/image/cimg/python

stb-tester/stb-tester,stb-tester/stb-tester,stb-tester/stb-tester,stb-tester/stb-tester