FR: Skip (implicit) "Post" step if run is canceled

[vorburger]

I've noticed (e.g. here) that when GitHub cancels a run (because of this cancel-in-progress: true etc.) then the Post Cache Bazel step still runs, for 47s, and saves cache artifacts.

Other actions such as notably https://github.com/actions/cache however seem to have some built-in magic which makes their Post... step being skipped somehow - the GitHub UI shows those with a striken through (/) sort of icon (whereas Post Bazel Cache is ☑️).

Perhaps it would be possible to implement whatever does this skipping in this action as well?

[p0deje]

I think the key here is that they use https://github.com/actions/cache/blob/9255dc7a253b0ccc959486e2bca901246202afeb/action.yml#L44

  post-if: "success()"

We can try to use a similar approach:

  post-if: "!cancelled()"

If you're up to test this and send PR, I'd be glad to merge.