Replace travis with GitHub Actions workflow

[Legion2]

Create docker.yml workflow and removed travis.yml close #43 Also updated docker-entrypoint.sh permissions in git

@bastilimbach setup DOCKER_USERNAME and DOCKER_PASSWORD in the Settings > Secrets

The images are build on push and pull request on any branch. The images a only pushed from the master branch. The workflow is also triggered by cron on the master branch every day at 3:17 UTC.

The workflow uses the docker-buildx action by CrazyMax

I did not test the push to docker hub but only the build operation.

[bastilimbach]

Awesome, thank you! 😍 I’ll take a look at this later. Is the docker buildx action by CrazyMax stable? What happens if they doesn’t maintain it any more?

[Legion2]

If CrazyMax deletes his action we need to find a new one or use a fork. But 139 stars for an action is much so I don't think it will disappear.

[Legion2]

I will update this PR to use the official docker actions https://github.com/crazy-max/ghaction-docker-buildx#moved-to-docker-organization

[Legion2]

Travis.org is shutting down, so this project must be migrated to travis.com or switch to github actions.