docs: mismatched namespace example of gatewayproxy (#2682) (#373)

(cherry picked from commit dcf3b593333e2b326a5ab76272a0dee2ac2e6b48)

Co-authored-by: Zeping Bai <[email protected]>

Author: github-actions[bot]

docs/en/latest/upgrade-guide.md

@@ -108,15 +108,14 @@ From version 2.0.0, the data plane must be connected via the `GatewayProxy` CRD:
 apiVersion: networking.k8s.io/v1
 kind: IngressClass
 metadata:
-  namespace: ingress-apisix
   name: apisix
 spec:
   controller: "apisix.apache.org/apisix-ingress-controller"
   parameters:
     apiGroup: "apisix.apache.org"
     kind: "GatewayProxy"
     name: "apisix-proxy-config"
-    namespace: "default"
+    namespace: "ingress-apisix"
     scope: "Namespace"
 ---
 apiVersion: apisix.apache.org/v1alpha1