It looks like this is because we updated to Python3.9 recently, but that version isn't in the go test container, so it's skipping running the tests
This PR addresses the issue by making the python version configurable with an environment variable. I also made related warnings into hard errors so this doesn't slip through in the future
The golang environment tests are currently marked as passing, but silently failing: https://github.com/googleapis/google-cloud-go/issues/6368
It looks like this is because we updated to Python3.9 recently, but that version isn't in the go test container, so it's skipping running the tests
This PR addresses the issue by making the python version configurable with an environment variable. I also made related warnings into hard errors so this doesn't slip through in the future