Fix experimental flag example

povsister · povsister · commit 3189bdf52a76 · 2020-11-03T14:30:44.000+08:00
diff --git a/content/en/docs/reference/command-line-tools-reference/kubelet-tls-bootstrapping.md b/content/en/docs/reference/command-line-tools-reference/kubelet-tls-bootstrapping.md
@@ -243,7 +243,7 @@ for example:
 The validity duration of signed certificates can be configured with flag:
 
 ```
---experimental-cluster-signing-duration
+--cluster-signing-duration
 ```
 
 ### Approval
