[CI] Include zuul.d/jobs.yaml as a trigger for image jobs

Zuul ignored the reconfiguration of the job vars and did not run
the promotion job in https://review.opendev.org/c/nebulous/activemq/+/919799/4

Change-Id: I740a69db39c67f061054db6a38bbffb1377e945d

zuul.d/jobs.yaml

@@ -8,6 +8,7 @@
       - nebulous-optimiser-controller-container-images
     description: Build the container images.
     files: &image_files
+      - ^zuul\.d/jobs\.yaml$
       - ^
     vars: &image_vars
       promote_container_image_job: nebulous-optimiser-controller-upload-container-images