replace istio.io/rev label by istio-injection label to simplify the experience

Author: Mathieu Benoit

content/ingress-gateway/deploy-ingress-gateway.md

@@ -28,7 +28,7 @@ metadata:
   name: ${INGRESS_GATEWAY_NAMESPACE}
   labels:
     name: ${INGRESS_GATEWAY_NAMESPACE}
-    istio.io/rev: ${ASM_VERSION}
+    istio-injection: enabled
     istio-discovery: enabled
 EOF
 ```

content/onlineboutique/set-up-onlineboutique-git-repo.md

@@ -29,7 +29,7 @@ metadata:
   name: ${ONLINEBOUTIQUE_NAMESPACE}
   labels:
     name: ${ONLINEBOUTIQUE_NAMESPACE}
-    istio.io/rev: ${ASM_VERSION}
+    istio-injection: enabled
     istio-discovery: enabled
 EOF
 ```

content/service-mesh/enforce-policies.md

@@ -46,7 +46,7 @@ spec:
     - resource-group-system
   parameters:
     labels:
-    - key: istio.io/rev
+    - key: istio-injection
     - key: istio-discovery
 EOF
 ```

content/whereami/set-up-whereami-git-repo.md

@@ -29,7 +29,7 @@ metadata:
   name: ${WHEREAMI_NAMESPACE}
   labels:
     name: ${WHEREAMI_NAMESPACE}
-    istio.io/rev: ${ASM_VERSION}
+    istio-injection: enabled
     istio-discovery: enabled
 EOF
 ```