Use Rocky 9 for continuous integration

[ninotarantino]

Closes #85

[ninotarantino]

Note: just delete the builds.yml file for now. It emails you on every push that no jobs were run.

[ninotarantino]

Seeing a small handful of intermittent verification data changes locally, as expected. Pushing a cleanup of current changes and will test the verif sims shortly.

Example: one single diff at t=73.5 of the Twist Sway model's RUN_00_baseline test: ts_so.ts.sway_parallel changes from 0.0852934028944027 meters to 0.08529340289440268 meters. That matches what I saw in the CentOS 7 to Rocky 8 upgrade.

[ninotarantino]

We're running out of memory during the sim builds. I'm going to try staggering the builds/runs/comparisons by model category and purging the artifacts afterwards.

[coveralls]

coverage: 88.329% (-1.1%) from 89.461% — use-rocky9-for-ci into main

[ninotarantino]

Finally got the builds passing. Summary of changes:

• Had to split the verification sims into their constituent model subcategories (dynamics, environment, etc). We were running out of memory during the build process, which doesn't even consider the logged data that'll be generated during the sim runs themselves. We've hit this before but sporadically on Rocky 8. Not sure whether the builds genuinely are that much bigger on Rocky 9, but it's not worth keeping a potential failure source around even if not, because we know for a fact that the total built size of CML exceeds the guaranteed memory allocation for free-tier GitHub Actions.
• Moved the coverage uploads to a separate job from the actual tests. Now it uses the default Ubuntu runner, downloads the XML file, and runs Coveralls from there. The Rocky 9 container doesn't have bash installed, and installing it during the first stage of the job doesn't work for the Coveralls action. We may be able to move this back into the main test job as part of Investigate custom docker image for main CI job #130.

I'll push a change to remove a debug print I accidentally kept committed and merge this tomorrow morning. CC @ddj116