Feature: Concurrency
Documented for v0.0.20 and included in the recommended workflow
Added in April 2021, GitHub Actions: Limit workflow run or job concurrency.
You're welcome to use this however you choose. Note that at the time this page was written, the feature was in beta.
If you aren't using Only changes, you probably want to use cancel-in-progress: true for the main spell check job.
For Update expect list, my recommended flow is to let both run but use concurrency to serialize the updates. I'm not sure if this is the right answer in general, and I don't know if this is the right answer for your project. I'm welcome implementation experience.
This "feature" doesn't involve any changes to the action itself, it's purely a function of the workflow.
You can see an implementation of it in spell-check-this.
When triggered, you'll get an event like this:
Canceling since a higher priority waiting request for 'spelling-refs/heads/prerelease' exists