add Priority to the list of recommended admission controllers (kubernetes#12180)

Author: bsalamat

content/en/docs/reference/access-authn-authz/admission-controllers.md

@@ -634,7 +634,7 @@ For Kubernetes version 1.10 and later, we recommend running the following set of
 {{< /note >}}
 
 ```shell
---enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,ResourceQuota
+--enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,Priority,ResourceQuota
 ```
 
 For Kubernetes 1.9 and earlier, we recommend running the following set of admission controllers using the `--admission-control` flag (**order matters**).