add initial docker push workflow

[rndmh3ro]

This adds a workflow to push images to dockerhub.

You need to create two variables in the repo for the username and token:

          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

This pushes two tags: latest and the git-tag.

I couldn't test it but hope that it will mostly work and you can then iterate on it.

[dimabru]

Hey @rndmh3ro
I've added the required secrets and approved the workflow :)

Few things to note here:

1. I suggest adding a temp workflow to test this behavior (you can trigger it on push to branch)
2. We need to make a slight change to the contents of the Dockerfile as well.
   The following line is no longer required since we don't need to pull anything from github anymore
   RUN curl -H "Authorization: token $GITHUB_TOKEN" --silent "https://api.github.com/repos/allero-io/allero-wip/releases/latest" | grep '"tag_name":' | sed -E 's/.*"([^"]+)".*/\1/' > cli-version
   Instead, you can inject the cli version to the Dockerfile using --build-arg

[dimabru]

Thanks for this pr :)
Please see comment above

[rndmh3ro]

So I got it to work.
Here's a successful run: https://github.com/rndmh3ro/allero/actions/runs/3197224646/jobs/5220160129
Here are the images: https://hub.docker.com/r/rndmh3ro/allero-cli/tags

[dimabru]

Amazing!!
Thanks a lot :)