Cloud Build: Some chores. (#11633)

* Cloud Build: Remove comment.

* Cloud Build: Add newlines at EOF.

* Cloud Build: Align comment.

* Cloud Build: Remove trailing slash.

* Cloud Build: Remove quotes.

* Cloud Build: Align indentation.

* Cloud Build: Improve quotes.

* Cloud Build: Put arguments in one line.

* Cloud Build: Bump image.

* Cloud Build: Reorder entrypoint.

* Cloud Build: Adjust timeouts.

* Cloud Build: Remove useless files.

* Cloud Build: Remove `substitution_option`.

images/ext-auth-example-authsvc/TAG

@@ -1 +1 @@
-v0.0.3
+v0.0.3

images/ext-auth-example-authsvc/cloudbuild.yaml

@@ -1,19 +1,8 @@
-timeout: 1200s
-options:
-  substitution_option: ALLOW_LOOSE
-  # job builds a multi-arch docker image for amd64,arm,arm64 and s390x.
-  machineType: E2_HIGHCPU_8
 steps:
-  - name: gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20211118-2f2d816b90
-    entrypoint: bash
+  - name: gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20240523-a15ad90fc9
     env:
-      - DOCKER_CLI_EXPERIMENTAL=enabled
       - REGISTRY=gcr.io/k8s-staging-ingress-nginx
-      # default cloudbuild has HOME=/builder/home and docker buildx is in /root/.docker/cli-plugins/docker-buildx
-      # set the home to /root explicitly to if using docker buildx
-      - HOME=/root
+    entrypoint: bash
     args:
-    - -c
-    - |
-      gcloud auth configure-docker \
-      && cd images/ && make NAME=ext-auth-example-authsvc push
+      - -c
+      - gcloud auth configure-docker && cd images && make NAME=ext-auth-example-authsvc push