Update ldap-deployment.yaml

Update example to the latest version of kubernetes

example/kubernetes/simple/ldap-deployment.yaml

@@ -1,10 +1,13 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: ldap
   labels:
     app: ldap
 spec:
+  selector:
+    matchLabels:
+      app: ldap
   replicas: 1
   template:
     metadata: