create release pipeline on main branch

[seebi]

Is your feature request related to a problem? Please describe.

We need a release pipeline in order to release jod automatically with github mechanics.

[white-gecko]

There is a pipeline to build a docker/podman image available now, the gem release is still missing.

[seebi]

docker is enough maybe? so close the ticket

[white-gecko]

No, gem should be published as well and should not be to complicated, cf. https://github.com/AKSW/jekyll-rdf/blob/develop/.travis.yml, this did publish gems back then.

[white-gecko]

Maybe https://github.com/marketplace/actions/publish-to-rubygems