artifact-registry: update docker-in-docker config
The "improvements" in https://gitlab.developers.cam.ac.uk/uis/devops/devhub/gitlab-runner-infrastructure/-/issues/12 have broken this job. Need to add a docker-in-docker service to fix.
GitLab will be upgraded on 14-Jan-2025 between 12:00 and 14:00. There may be small periods of service instability.
The "improvements" in https://gitlab.developers.cam.ac.uk/uis/devops/devhub/gitlab-runner-infrastructure/-/issues/12 have broken this job. Need to add a docker-in-docker service to fix.