ci: update workflow-template

Add `ls -la /workspace/cache` to prepare step

This lists the contents of the cache directory after the prepare
step completes to help debug caching issues.

Author: in-jun

chart/templates/app/ci/workflow-template.yaml

@@ -72,6 +72,7 @@ spec:
             git rev-parse HEAD > /workspace/sha.txt
             echo "[PREPARE] Process completed with SHA:"
             cat /workspace/sha.txt
+            ls -la /workspace/cache
         env:
           - name: GIT_USERNAME
             valueFrom: