ci: setting up samples_build.yaml (2) (#1930)

Enhancing the sample_build.yaml gradually. Current status:

- AdminIT failed
- DeadLetterQueueIT succeeded
- PublisherIT succeeded
- SchemaIT succeeded
- SubscriberIT succeeded

Merging this for now as this has good progress itself. We'll address AdminIT in a subsequent pull request.

.cloudbuild/samples_build.yaml

@@ -1,17 +1,31 @@
 steps:
-- name: gcr.io/cloud-devrel-kokoro-resources/java8
+- name: gcr.io/cloud-devrel-public-resources/java8
   entrypoint: ls
   args: [
     '-alt',
   ]
-- name: gcr.io/cloud-devrel-kokoro-resources/java8
+- name: gcr.io/cloud-devrel-public-resources/java8
+  entrypoint: curl
+  args: [
+    '--header',
+    'Metadata-Flavor: Google',
+    'http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/email'
+  ]
+- name: gcr.io/cloud-devrel-public-resources/java8
   entrypoint: pwd
-- name: gcr.io/cloud-devrel-kokoro-resources/java8
+- name: gcr.io/cloud-devrel-public-resources/java8
   entrypoint: bash
   args: [
-    './kokoro/build.sh'
+    '.kokoro/build.sh'
   ]
   env:
   - 'JOB_TYPE=samples'
-
-timeout: 300m
+  - 'GOOGLE_CLOUD_PROJECT=cloud-java-ci-sample'
+- name: gcr.io/cloud-devrel-public-resources/java8
+  entrypoint: echo
+  args: [
+    'Sample job succeeded',
+  ]
+timeout: 3600s
+options:
+  defaultLogsBucketBehavior: REGIONAL_USER_OWNED_BUCKET