Add docker tags and label

[pablosproject]

Tries to solve #140. By default this action adds the tag of the current branch and also add the latest tag to the latest image pushed.

It should also add the commit sha as a tag, useful to get a specific commit image (in case of regression, etc).
Try and see if it can work for the project. Otherwise we can customize tags using the rules here https://github.com/docker/metadata-action#usage.

I tried on my end by logging out the output and all seems to be working fine.

[guysoft]

Looks like its working, but I need to test the tags.

[pablosproject]

Ok, let me know if I can help with that.

[guysoft]

@pablosproject Hey qustion -
if the branch is master, is there a way to append the tag latest to llabels: ${{ steps.docker_meta.outputs.labels }}?
Can't find anywhere how to do that

[pablosproject]

Yes, you need to add a custom input to the action using the flavor input. As for default configuration, it's generated automatically every time you push a tag, no matter the branch.

Otherwise, you need to write your own custom naming strategy, not sure how to do that. For my use cases the default strategy is the most logical.

[guysoft]

Related: https://github.com/docker/build-push-action/issues/503