Update README.md

Author: WangXiangUSTC

README.md

@@ -13,6 +13,10 @@ CoreDNS running with the k8s_dns_chaos plugin can be used to do chaos tests on D
 
 This plugin can only be used once per Server Block.
 
+> **Note:** 
+>
+> It works with CoreDNS 7d5f5b87a4fb310d442f7ef0d52e3fead0e10d39.
+
 ## Syntax
 
 ~~~
@@ -80,4 +84,4 @@ The shell command below will execute failed:
 ```shell
     kubectl exec busybox-0 -it -n busybox -- ping -c 1 google.com
     ping: bad address 'google.com'
-```
+```