examples/cluster-api-server: add missing version in RoleBinding

Fixes "Error from server (NotFound): error when
       creating "examples/cluster-api-server.yaml":
       the server could not find the requested resource

examples/cluster-api-server.yaml

@@ -102,7 +102,7 @@ spec:
         hostPath:
           path: /etc/ssl/certs
 ---
-apiVersion: rbac.authorization.k8s.io/
+apiVersion: rbac.authorization.k8s.io/v1
 kind: RoleBinding
 metadata:
   name: clusterapi