gep-713: correct label value (#2660)

* gep-713: correct label value

The value should be the policy type, not `true`.
Signed-off-by: spacewander <[email protected]>

* Update geps/gep-713.md

Co-authored-by: Rob Scott <[email protected]>

---------

Co-authored-by: Rob Scott <[email protected]>

Author: spacewander

geps/gep-713.md

@@ -1253,8 +1253,8 @@ will be capable of describing the computed sum of policy that applies to a given
 resource, including policies applied to parent resources.
 
 Each Policy CRD that wants to be supported by this plugin will need to follow
-the API structure defined above and add a `gateway.networking.k8s.io/policy: true`
-label to the CRD.
+the API structure defined above and add the [corresponding label](https://gateway-api.sigs.k8s.io/geps/gep-713/#standard-label-on-crd-objects)
+to the CRD.
 
 ### Conditions