doc: remove reference of deprecated upstream image

The kube-rbac-proxy from upstream is deprecated. Therefore, it's better not to include it in the examples since we do not promote its usage. PS. it does not seems to bring any value. Follow up of operator-framework#336

Signed-off-by: Camila Macedo <7708031+camilamacedo86@users.noreply.github.com>

Author: camilamacedo86

content/en/docs/Reference/catalog-templates.md

@@ -114,8 +114,6 @@ properties:
     packageName: example-operator
     version: 0.2.0
 relatedImages:
-- image: gcr.io/kubebuilder/kube-rbac-proxy:v0.8.0
-  name: ""
 - image: docker.io/example/example-operator-bundle:0.2.0
   name: ""
 - image: docker.io/example/example-operator:0.2.0