Add BUILDER_IMAGE_REVISION to cache keys
If something changes in the builder, we need to be aware of this in the depenedent builds, and not use cached artefacts generated by eariler builders.
Here we thread BUILDER_IMAGE_REVISION through the cache keys that previous just used the job name/branch caches.
From the investigation of #3032 (closed)
Fixes: #2821 (closed)
Edited by GitLab Release Tools Bot