doc(tutorials/rfc2136): fix RBAC (#5827)

Author: vflaux

docs/tutorials/rfc2136.md

@@ -203,13 +203,20 @@ rules:
   - ""
   resources:
   - services
-  - endpoints
   - pods
   - nodes
   verbs:
   - get
   - watch
   - list
+- apiGroups:
+  - discovery.k8s.io
+  resources:
+  - endpointslices
+  verbs:
+  - get
+  - watch
+  - list
 - apiGroups:
   - extensions
   - networking.k8s.io