Updated GitHub Action

[danielwagn3r]

Enable conditional push to Docker Hub (only for release tags)
Enable Dependabot

[danielwagn3r]

As promised a reworked GitHub Action.

Required Secrets:

• DOCKERHUB_IMAGENAME, e.g gilleslamiral/imapsync
• DOCKERHUB_TOKEN, i.e a Docker Hub Personal Access Token to be able to push images
• DOCKERHUB_USERNAME, e.g. gilleslamiral

The action runs on every push to master, but only pushes if a new matching tag was created - the tag ist then used for the Docker tag as well.

[danielwagn3r]

If you somewhen plan have the latest imapsync version on GitHub the Dockerfile can be optimized further, to get rid of the wget which is currently used.

[gilleslamiral]

Thanks for this request.
The problem is that I don't want to trigger a Docker image creation and publishing without testing it before.

[danielwagn3r]

Full understandable, I'm used to this as well. Therefore, the proposed Action only triggers when a release is tagged in the Git repository.