Adding endpoints resource permission (kubernetes-sigs#1580)

According to kubernetes-sigs/external-dns#961 (comment), an `endpoints` resource permission is needed 
I'm using EKS 1.17

Author: tsahiduek

docs/examples/external-dns.yaml

@@ -20,6 +20,9 @@ rules:
 - apiGroups: [""]
   resources: ["nodes"]
   verbs: ["list"]
+- apiGroups: [""]
+  resources: ["endpoints"]
+  verbs: ["get", "watch", "list"]
 ---
 apiVersion: rbac.authorization.k8s.io/v1beta1
 kind: ClusterRoleBinding