Use github ci

[sbellem]

• Fix PR case, from forks. Login to Dockerhub can only work for the org repo, not for forks. For forks, only build; no login, no push.
• Update Dockerhub description from README.md file of this repo. See Update Readme and description with push on Docker hub docker/build-push-action#21 for ideas on how to do so; (e.g.: https://github.com/marketplace/actions/docker-hub-description). NOTE: No PAT support -- see feature request: provide way to update a repo's description and full_description docker/hub-tool#172 (comment).
• Add missing older versions from .travis.yml