Don't mention kubeadm dual-stack as a site front page feature

kubeadm dual-stack is a nice feature, but we don't need to mention it
on https://kubernetes.io/

Omit that mention.

Author: Tim Bannister

content/en/docs/setup/production-environment/tools/kubeadm/dual-stack-support.md

@@ -1,7 +1,5 @@
 ---
 title: Dual-stack support with kubeadm
-feature:
-  title: Dual-stack support with kubeadm
 content_type: task
 weight: 110
 min-kubernetes-server-version: 1.21