* Fix variable substitutions in CD workflow and gcloud build config
* Docker needs everything lowercase
* Store container image in GCR
* Don't use GITHUB_REPOSITORY
* Add CI workflow similar to other zebra
* Bump cache TTL to 24hours
* Expand image name to include full repo owner/repo-name/branch-name
* Force to lowercase because google container registry demands it
This may not be universally shell compatible
* Use bash as gcloud action container entrypoint