[en] update en docs to use recommended labels

content/en/docs/concepts/services-networking/dual-stack.md

@@ -37,7 +37,7 @@ IPv4/IPv6 dual-stack on your Kubernetes cluster provides the following features:
 
 The following prerequisites are needed in order to utilize IPv4/IPv6 dual-stack Kubernetes clusters:
 
-* Kubernetes 1.20 or later  
+* Kubernetes 1.20 or later
 
   For information about using dual-stack services with earlier
   Kubernetes versions, refer to the documentation for that version
@@ -95,7 +95,7 @@ set the `.spec.ipFamilyPolicy` field to one of the following values:
 
 If you would like to define which IP family to use for single stack or define the order of IP
 families for dual-stack, you can choose the address families by setting an optional field,
-`.spec.ipFamilies`, on the Service. 
+`.spec.ipFamilies`, on the Service.
 
 {{< note >}}
 The `.spec.ipFamilies` field is immutable because the `.spec.ClusterIP` cannot be reallocated on a
@@ -133,11 +133,11 @@ These examples demonstrate the behavior of various dual-stack Service configurat
    address assignments. The field `.spec.ClusterIPs` is the primary field, and contains both assigned
    IP addresses; `.spec.ClusterIP` is a secondary field with its value calculated from
    `.spec.ClusterIPs`.
-   
+
    * For the `.spec.ClusterIP` field, the control plane records the IP address that is from the
-     same address family as the first service cluster IP range. 
+     same address family as the first service cluster IP range.
    * On a single-stack cluster, the `.spec.ClusterIPs` and `.spec.ClusterIP` fields both only list
-     one address. 
+     one address.
    * On a cluster with dual-stack enabled, specifying `RequireDualStack` in `.spec.ipFamilyPolicy`
      behaves the same as `PreferDualStack`.
 
@@ -174,7 +174,7 @@ dual-stack.)
    kind: Service
    metadata:
      labels:
-       app: MyApp
+       app.kubernetes.io/name: MyApp
      name: my-service
    spec:
      clusterIP: 10.0.197.123
@@ -188,7 +188,7 @@ dual-stack.)
        protocol: TCP
        targetPort: 80
      selector:
-       app: MyApp
+       app.kubernetes.io/name: MyApp
      type: ClusterIP
    status:
      loadBalancer: {}
@@ -214,7 +214,7 @@ dual-stack.)
    kind: Service
    metadata:
      labels:
-       app: MyApp
+       app.kubernetes.io/name: MyApp
      name: my-service
    spec:
      clusterIP: None
@@ -228,7 +228,7 @@ dual-stack.)
        protocol: TCP
        targetPort: 80
      selector:
-       app: MyApp
+       app.kubernetes.io/name: MyApp
    ```
 
 #### Switching Services between single-stack and dual-stack