Add a job to publish a docker image on merge
Before raising this MR, consider whether the following are required, and complete if so:
-
Unit tests -
Metrics -
Documentation update(s)
If not required, please explain in brief why not.
A CI change. We should update the documentation, but only once there is at least one image actually published.
Description
This MR adds a CI job to build and publish a docker image to the GitLab registry for this repository when MRs get merged. This means we'll only be maintaining a single Dockerfile, rather than testing with one and publishing another. Publishing for each merge also makes it easier to pin a specific version of BuildGrid than it currently is, since there is no versioning in the existing nightly build.