Making an optional, required, status check with GitHub Actions

Something that I've hit time and time again over the years - but seemingly have never blogument'd - is that when you add a required status check on GitHub (in branch protection or a Ruleset), it needs to report back as successful before you can merge a given Pull Request. This is absolutely reasonable, and I don't think there are many complaints folks would have about this requirement. That is, until you want to consider how to handle checks that you don't necessarily want to run all the time. For instance, let's say you have a smallish monorepo where there is a mix of Java, backend Typescript and frontend React + Typescript. If you're only changing one of those parts of the codebase - or if you're fixing a typo in a Markdown file - you probably don't want to run all three suites of tests. There may be cases where the frontend needs to re-run its tests if there's a change in the backend code for instance if you've got tests that collaborate on the state of the API contract, but for…