* ensure $BRANCH is always the same value (borrowed from Sonobuoy)
* get gcloud SDK installed (borrowed from Sonobuoy)
* use deploy step to run GCR push script (borrowed from Sonobuoy)
* use gcloud's docker to do the image building/pushing
* placeholders for secure values
* rename $LATEST to $HIGHEST to more accurately reflect what it is
Signed-off-by: Nolan Brubaker <brubakern@vmware.com>