Install sbt via brew on macOS runners

[armanbilge]

Fixes #680. To keep things simple we do the install for all macOS runners.

[mzuehlke]

Good solution.

While looking at the generate ci.yml
I see that all jobs except "Build and Test" contain a lot of steps that will never be executed because of their guards, and all the other jobs are only running on "ubuntu".

[armanbilge]

Thanks!

While looking at the generate ci.yml
I see that all jobs except "Build and Test" contain a lot of steps that will never be executed because of their guards, and all the other jobs are only running on "ubuntu".

Yes this is currently the case because we use githubWorkflowJobSetup for all jobs. If we are clever we could probably filter irrelevant steps. In practice, it doesn't matter too much besides the bloat/noise.