Add missing feature gate ServiceAccountNodeAudienceRestriction

Author: tengqm

content/en/docs/reference/command-line-tools-reference/feature-gates/ServiceAccountNodeAudienceRestriction.md

@@ -0,0 +1,18 @@
+---
+title: ServiceAcccountNodeAudienceRestriction
+content_type: feature_gate
+_build:
+  list: never
+  render: false
+
+stages:
+  - stage: beta
+    defaultValue: false
+    fromVersion: "1.32"
+    toVersion: "1.32"
+  - stage: beta
+    defaultValue: true
+    fromVersion: "1.33"  
+
+---
+This gate is used to restrict the audience for which the kubelet can request a service account token for.