deprecate run argument to actions

[maxheld83]

it appears that the runs arguments to actions (which used to just be appended to docker run as COMMAND and ARGS), has been deprecated.

Now you can only overwrite entrypoint and args separately.

Like so:

- name: Download Cache
        uses: actions/gcloud/cli@d124d4b82701480dc29e68bb73a87cfb2ce0b469
        with:
          entrypoint: gsutil
          args: -m cp -r gs://ghactions-cache/lib.tar.gz /github/home/

Whereas before, we could:

action "Download Cache" {
  uses = "actions/gcloud/cli@d124d4b82701480dc29e68bb73a87cfb2ce0b469"
  runs = "gsutil -m cp -r gs://ghactions-cache/lib.tar.gz /github/home/"
}

Not a huge limitation, but something to be aware of.
Just slightly less convenient, I guess.

[maxheld83]

also need to verify this with support.

[maxheld83]

wrote to support to verify:

on the old, HCL-based github actions there was a runs parameter, which would just be prepended to docker run ... as COMMAND and ARGS, effectively overwriting any default entrypoint and args.

It appears that this is now no longer supported via steps.with.*, but you only have entrypoint and args, which can achieve the same result.

More details here: #338

Do I have this right?

If so, it might be worthwhile a) to add it back in, or b) to note in the docs that runs has been deprecated, because it's something the old actions could do.
Probably makes more sense to deprecate, since it was always a bit confusing/redundant.