test compose workflow

* docker-compose test workflow to broadly approximate the getting started guide,
since testing on balenaCloud/balenaOS alone doesn't give us a high level of
confidence the project boots/works on compose

change-type: minor

.github/workflows/flowzone.yml

@@ -50,8 +50,3 @@ jobs:
         github.event_name == 'pull_request_target'
       )) && github.event.action != 'closed'
     secrets: inherit
-    with:
-      environment: balena-cloud.com
-      fleet: balena/open-balena
-      # https://dash.cloudflare.com/001b3ed2352612aaa068aca1b0022736/balena-devices.com/dns
-      dns_tld: balena-devices.com