doc: runtimeConfig can be used to enable deprecated APIs

Author: kalexmills

site/content/docs/user/configuration.md

@@ -86,13 +86,14 @@ featureGates:
 
 Kubernetes API server runtime-config can be toggled using the `runtimeConfig`
 key, which maps to the `--runtime-config` [kube-apiserver flag](https://kubernetes.io/docs/reference/command-line-tools-reference/kube-apiserver/).
-This may be used to e.g. disable beta / alpha APIs.
+This may be used to e.g. disable beta / alpha APIs, or even enable deprecated APIs.
 
 {{< codeFromInline lang="yaml" >}}
 kind: Cluster
 apiVersion: kind.x-k8s.io/v1alpha4
 runtimeConfig:
   "api/alpha": "false"
+  "apps/v1beta2": "true"
 {{< /codeFromInline >}}
 
 ### Networking