Publish pre-built docker container image to ghcr.io or docker-hub

[jo-chemla]

Hi here,
Long time crontab-guru user, I just discovered you built a really nice crontab.guru/dashboard.
The docs explain how to build your own container images, with build arguments, to be used in a docker-compose stack.

It would be great for selfhosters for the pre-built crontab-guru dashboard container image to be published on an image repository like ghcr.io or dockerhub!