Simplify argocd exclusion pattern to fix discovery issue

Change from multiline exclude with **/ pattern to simple single-line
'argocd/**' pattern relative to apps/ path.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/app-stack-basicstack-de.yaml

@@ -11,8 +11,7 @@ spec:
     path: apps
     directory:
       recurse: true
-      exclude: |
-        **/argocd/**
+      exclude: 'argocd/**'
   destination:
     server: https://kubernetes.default.svc
   syncPolicy: