RHOAIENG-38634: add latest additional tags for c9s Docker base image (opendatahub-io#2665)

Author: jiridanek

.tekton/odh-base-image-cpu-py312-c9s-push.yaml

@@ -28,6 +28,10 @@ spec:
     value: base-images/cpu/c9s-python-3.12/Dockerfile.cpu
   - name: path-context
     value: .
+  - name: additional-tags
+    value:
+    - '{{target_branch}}-{{revision}}'
+    - latest
   - name: build-platforms
     value:
     - linux/x86_64