the pod yaml type error and add apiVersion

docs/tasks/inject-data-application/podpreset.md

@@ -325,34 +325,35 @@ spec:
 **Pod spec after admission controller:**
 
 ```yaml
+apiVersion: v1
 kind: Pod
-  metadata:
-    labels:
-      app: guestbook
-      tier: frontend
-    annotations:
+metadata:
+  labels:
+    app: guestbook
+    tier: frontend
+  annotations:
     podpreset.admission.kubernetes.io/podpreset-allow-database: "resource version"
-  spec:
-    containers:
-      - name: php-redis
-        image: gcr.io/google_samples/gb-frontend:v3
-        resources:
-          requests:
-            cpu: 100m
-            memory: 100Mi
-        volumeMounts:
-          - mountPath: /cache
-            name: cache-volume
-        env:
-          - name: GET_HOSTS_FROM
-            value: dns
-          - name: DB_PORT
-            value: "6379"
-        ports:
-          - containerPort: 80
-    volumes:
-      - name: cache-volume
-        emptyDir: {}
+spec:
+  containers:
+  - name: php-redis
+    image: gcr.io/google_samples/gb-frontend:v3
+    resources:
+      requests:
+        cpu: 100m
+        memory: 100Mi
+    volumeMounts:
+    - mountPath: /cache
+      name: cache-volume
+    env:
+    - name: GET_HOSTS_FROM
+      value: dns
+    - name: DB_PORT
+      value: "6379"
+    ports:
+    - containerPort: 80
+  volumes:
+  - name: cache-volume
+    emptyDir: {}
 ```
 
 ### Multiple PodPreset Example