Just got hit by https://github.com/actions/runner-images/issues/6002.

We need to upgrade the version of ubuntu that azure pipelines is using. Unfortunately, it won't be as simple as just switching to ubuntu 22.04 or 20.04 as neither support python3.7 without adding the deadsnakes repo. Upgrading to python 3.8 or later will trigger an upgrade of some other test dependencies (typed_ast) that are being intentionally held back due to incompatibilities with python 3.8+. At this point, pretty much all the dependencies in this repo are getting pretty ancient, and we should probably just do a full upgrade.