Fix failing CI actions

It looks like the CI setup is failing; for example here is a recent run: https://github.com/huongngo-8/open_whisper/actions/runs/8144556704

I would suggest
* break the CI workflow into multiple separate workflows which run distinct tests (i.e. a separate test for linting, one that just builds the environment, and one to do something like training)
* Make sure all of the workflows are passing
* Add a badge for each workflow to the README https://docs.github.com/en/actions/monitoring-and-troubleshooting-workflows/adding-a-workflow-status-badge