Update apiVersion of Deployment to apps/v1 in v1.9 (#7163)

docs/user-guide/walkthrough/deployment-update.yaml

@@ -1,8 +1,11 @@
-apiVersion: apps/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: nginx-deployment
 spec:
+  selector:
+    matchLabels:
+      app: nginx
   replicas: 2
   template:
     metadata:

docs/user-guide/walkthrough/deployment.yaml

@@ -1,8 +1,11 @@
-apiVersion: apps/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: nginx-deployment
 spec:
+  selector:
+    matchLabels:
+      app: nginx
   replicas: 2 # tells deployment to run 2 pods matching the template
   template: # create pods using pod definition in this template
     metadata: