add build and push to ghcr similar to danger

[wilkyd]

Copy of danger/danger#1445 & 1446 fix for JS

[orta]

Thanks

[orta]

I'm going to revert this as it is a breaking change - we were shipping to docker before and this removes that feature for people who were using it

I'm open to a version which ships to both, but not breaking folks' existing workflows

[wilkyd]

Not sure I understand, both the original workflow and the updated workflow seem to solely push the Docker image to the GitHub Container Registry (ghcr.io). I don't see any push to Docker Hub or other registries. Could you please specify the breaking change? Thanks

[orta]

Hah, sorry, I misread the older build logs!

[wilkyd]

Thanks! We would now recommend folk to use the image (docker://ghcr.io/danger/danger:main) when it is released rather than danger/danger documented in the CI section. So something like:

jobs:
  my_first_job:
    steps:
      - name: My first step
        uses: docker://ghcr.io/danger/danger:main

I don't mind creating an official action in another repo with a tag input if it would make the usage clearer.