test-daily.yml: also run this on push to main (and rename it)

[fingolfin]

Right now, during the time after a package update is merged, and before the cron job for test-daily.yml runs, incorrect reporting may be issued: Indeed, the UGALY package was failing; I'ver merged an update for it that caused tests to pass. Now all the new reports for other PRs claim that that other PR fixed UGALY, because UGALY is passing on main now, but wasn't last night.

While this is not terribly bad, it is annoying. And all in all, I think it's a good idea to run those tests on master anyway...

One way to do it would be to simply use the same filters as assemble-distro.yml uses, i.e.:

  push:
    paths:
      - 'packages/*/meta.json'
    branches:
      - main

But actually perhaps we should instead do something slightly different: because it would actually be good if the archives assembled by assemble-distro.yml were tested... so perhaps we can add an input to test-all.yml which makes it use those archives instead ... see also issue #200... and also #156

[fingolfin]

Done in f23b9b4