fix(k8s): update labels and selectors for consistency

Change label keys from "app" to "app.kubernetes.io/name"  
to standardize the label format across the deployment,  
service, and pod specifications. This improves clarity and  
ensures alignment with Kubernetes best practices for  
labeling and facilitates better management and  
selection of resources.

k8s/deploy.yaml

@@ -3,7 +3,7 @@ kind: Deployment
 metadata:
   name: unbound-site
   labels:
-    app: unbound-site
+    app.kubernetes.io/name: unbound-site
   annotations:
     kubernetes.io/change-cause: "${TIMESTAMP} Deployed commit id: ${COMMIT}"
 spec:
@@ -16,11 +16,11 @@ spec:
   minReadySeconds: 30
   selector:
     matchLabels:
-      app: unbound-site
+      app.kubernetes.io/name: unbound-site
   template:
     metadata:
       labels:
-        app: unbound-site
+        app.kubernetes.io/name: unbound-site
     spec:
       affinity:
         podAntiAffinity:
@@ -29,7 +29,7 @@ spec:
             podAffinityTerm:
               labelSelector:
                 matchExpressions:
-                - key: "app"
+                - key: "app.kubernetes.io/name"
                   operator: In
                   values:
                   - unbound-site
@@ -62,11 +62,11 @@ kind: Service
 metadata:
   name: unbound-site
   labels:
-    app: unbound-site
+    app.kubernetes.io/name: unbound-site
 spec:
   type: NodePort
   selector:
-    app: unbound-site
+    app.kubernetes.io/name: unbound-site
   ports:
   - port: 80
     targetPort: 80