different docker image

Author: dashpole

cloudbuild-e2e-image.yaml

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 steps:
-  - name: docker
+  - name: gcr.io/cloud-builders/docker:19.03.15
     entrypoint: "sh"
     args:
       - -c