As a Wikibase Release manager I want to be able to publish a release of the Wikibase extension so that it can be installed by the user.

This is about creating the initial "pipeline" that generates the release artifacts (tarball and docker container image) including Wikibase extension.
Compatible MediaWiki version is also released together in the container container format.

The "pipeline" is going to be gradually and iteratively extended, to publish releases of broader scope of software components.

Acceptance criteria

• Release artifacts of the arbitrary version (git commit) of Wikibase extension are published
  • as a tarball/zip
  • as a docker container image
• Code to be published is automatically tested prior to publishing
• Decision, including its rationale, on the scope of the automated testing of the code to be published has been documented as in the repo: https://github.com/wmde/wikibase-release-prototype
• Version of Mediawiki compatible with the published version of Wikibase is determine and made visible in the release results
• Docker container image contains the compatible version of MediaWiki software

Note we: say federated properties is out of scope for now