Custom pytest output for GHA

[dopplershift]

Looks like there's not currently any good options to take advantage of GitHub Actions' new support for outputting a job summary. While I'm sure something will develop over time, I kinda want to take advantage of this feature.

PyTest has plugins that can even be contained with conftest.py (though I'm not clear exactly what the API/hook-in points are--probably take looking at some real-world examples). pytest-md-report and pytest-html might have some good inspiration on features/formatting.

Thoughts to include:

• Failed tests--with trace
• XPassed tests
• Warnings?
• Images (subset) from failing tests?

The goal here would be to get useful information without needing to click into the logs every time.