Currently, [the API](https://docs.gitlab.com/ee/api/version.html) only contains the GitLab version (and the revision). It could be useful to be able to retrieve the Heptapod version as well. A possible use-case would be to check if Heptapod is up-to-date on a dashboard. I'm willing to work on this issue. --- Files to edit (probably): * app/models/instance_metadata.rb * spec/models/instance_metadata_spec.rb * lib/api/version.rb