Add GitHub Action job summaries to workflows

[desrosj]

In May, GitHub released ​Job Summaries for GitHub Actions, which allows markdown or raw HTML to be displayed on the workflow run summary page for jobs.

This ticket is for exploring ways to use this feature in the WordPress Core workflows to make it easier to understand the data and outcomes buried in each step's log output within a job.

[desrosj]

Was chatting with @johnbillion a bit in Slack about how this feature could be utilized in Core. He ​shared one example from a project of his.

After some discussion, the most apparent place that this could be useful is within the PHPUnit workflow to display a table with data around how many:

• tests were identified as risky.
• tests were skipped.
• tests encountered errors.
• total tests were found.
• assertions were made.
• etc.

I'm marking this as good-first-bug as it's self-contained, and a great way to dig in to learn more about GitHub Actions.

Trac ticket: https://core.trac.wordpress.org/ticket/56150

[desrosj]

I think it would be great to use this feature as a way to surface the results of the performance testing introduced in [55459].

The data is submitted to an external dashboard and is visible within the logs, but having it presented as a job summary would be really neat. cc/@joemcgill @flixos90 @mukesh27

[joemcgill]

I dig this idea. Thanks @desrosj!

[joemcgill]

I still really like the idea of displaying automated performance benchmarks on PRs using this method, but doing so should be preceded by #58358.

Since this ticket is only related to our build tools I'm changing it to a task ticket because it can be worked on outside the normal release cycle. @desrosj feel free to change it back if that's incorrect.

[swissspidy]

​https://github.com/WordPress/wordpress-develop/pull/5000 adds a summary for the performance tests

[whyisjake]

Reviewing tickets with @mikestraw at WCUS. Has a patch, needs testing.

[swissspidy]

In 56506:

Build/Test Tools: Compare results in performance measurement workflow.

This extends the performance test workflow added in [55459] to also run tests against the target branch (if running on a pull request) or the previous commit (if running on trunk).

Those results are then compared with the ones from the current commit, and the difference is displayed as a GitHub Actions workflow summary for convenience.

Props mukesh27, flixos90, desrosj, joemcgill, swissspidy.
Fixes #58358, #58359.
See #56150.

[joemcgill]

@desrosj Now that we've implemented GH Action summaries in [56506] and in the GB repo (see a summary from ​the Performance Test actions), I wonder if we can consider this complete and create follow-up issues for adding summaries to specific workflows?

[desrosj]

@joemcgill That makes sense to me. This was mainly meant as a reminder to see if there were valid uses for us!