minimize rbac permission by setting secret as optional

deploy/kubernetes/rbac.yaml

@@ -32,9 +32,13 @@ rules:
   - apiGroups: [""]
     resources: ["events"]
     verbs: ["list", "watch", "create", "update", "patch"]
-  - apiGroups: [""]
-    resources: ["secrets"]
-    verbs: ["get", "list"]
+  # Secret permission is optional.
+  # Enable it if your driver needs secret.
+  # For example, `csi.storage.k8s.io/snapshotter-secret-name` is set in VolumeSnapshotClass.
+  # See https://kubernetes-csi.github.io/docs/secrets-and-credentials.html for more details.
+  #  - apiGroups: [""]
+  #    resources: ["secrets"]
+  #    verbs: ["get", "list"]
   - apiGroups: ["snapshot.storage.k8s.io"]
     resources: ["volumesnapshotclasses"]
     verbs: ["get", "list", "watch"]