Allow bash-resolved value for labels

[tlienart]

TL;DR

labels: |-
    commit=$(git rev-parse --short ${{github.event.pull_request.head.sha}})

won't work (this is a specific example but, unless I'm mistaken, other similar $(...) will fail).

Log output

"error": {
    "code": 400,
    "message": "The request has errors",
    "status": "INVALID_ARGUMENT",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.BadRequest",
        "fieldViolations": [
          {
            "field": "labels",
            "description": "labels {(...) commit=\"$(git rev-parse --short XXX)\"} format is invalid"

^ looking at the log above seems to suggest that the value is just escaped and passed "as is". It'd be great to have the string potentially resolved first then passed to gcloud deploy.

[sethvargo]

There's no bash or shell running, so this is not possible.