Add versioning to docker container

[wuast94]

pls add a version tag to the docker containers. i run a swarm cluster and having just the latest tag always require some sort of 3rd lvl tool to keep a container up to date. adding semver versioning allowes for monitoring remote changes, review and deploy them in a easy and controlled way :)

[robinvalk]

Would love to see this container being released with versioning too! 👍