Change example of tagTemplate in config-network to the same value of …

…default (knative#6186)

As knative#6178 reported, the
default value of tagTemplate is:

https://github.com/knative/serving/blob/b8a17ae4bac00a9749ba65b822db697cd582df50/pkg/network/network.go#L119

which is opposite from the example in `config-network`. As discussed
in knative#3492, the example value
should be defaults to avoid confusion.

config/config-network.yaml

@@ -122,7 +122,7 @@ data:
     # when constructing the DNS name for "tags" within the traffic blocks
     # of Routes and Configuration.  This is used in conjunction with the
     # domainTemplate above to determine the full URL for the tag.
-    tagTemplate: "{{.Name}}-{{.Tag}}"
+    tagTemplate: "{{.Tag}}-{{.Name}}"
 
     # Controls whether TLS certificates are automatically provisioned and
     # installed in the Knative ingress to terminate external TLS connection.