Update the workloads API versions to 1.9 for rest of the docs (#7099)

* Update the workloads API versions to 1.9 for rest of the docs

* Remove comments per CR feedback

* Add a comment to be clear about which versions will work with the example

docs/admin/authentication.md

@@ -185,7 +185,7 @@ talk to the API server. Accounts may be explicitly associated with pods using th
 NOTE: `serviceAccountName` is usually omitted because this is done automatically.
 
 ```
-apiVersion: apps/v1beta2
+apiVersion: apps/v1 # this apiVersion is relevant as of Kubernetes 1.9
 kind: Deployment
 metadata:
   name: nginx-deployment

docs/tasks/inject-data-application/podpreset-replicaset.yaml

@@ -1,4 +1,4 @@
-apiVersion: apps/v1beta2
+apiVersion: apps/v1
 kind: ReplicaSet
 metadata:
   name: frontend