Update github actions

[danodonovan]

The actions are currently failing for a few reasons, including

• GitHub removed the in-use Ubuntu 20.04 hosted image
• actions/setup-python no longer provides Python 2.7

I suggest the repo changes / updates the actions so the CI can start running again.

[mwilliamson]

Thanks for the report! The workflow has been updated to work on ubuntu-22.04.