ci: add deploy job to trigger Cloud Build after integration tests

Add a deploy job that authenticates to GCP via Workload Identity
Federation and triggers the api-httpsms-com Cloud Build trigger
with the tested commit SHA. Only runs on push to main after
integration tests pass.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: AchoArnold

.github/workflows/api.yml

@@ -10,6 +10,7 @@ on:
 
 permissions:
   contents: read
+  id-token: write
 
 jobs:
   integration-test:
@@ -71,3 +72,24 @@ jobs:
         if: always()
         working-directory: ./tests
         run: docker compose down -v
+
+  deploy:
+    runs-on: ubuntu-latest
+    needs: integration-test
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    steps:
+      - name: Authenticate to Google Cloud 🔐
+        uses: google-github-actions/auth@v2
+        with:
+          workload_identity_provider: ${{ secrets.GCP_WORKLOAD_IDENTITY_PROVIDER }}
+          service_account: ${{ secrets.GCP_SERVICE_ACCOUNT }}
+
+      - name: Set up Cloud SDK ☁️
+        uses: google-github-actions/setup-gcloud@v2
+
+      - name: Trigger Cloud Build Deploy 🚀
+        run: |
+          gcloud builds triggers run api-httpsms-com \
+            --region=global \
+            --project=httpsms-86c51 \
+            --sha=${{ github.sha }}