fix readme

Author: Liuchy1

README.md

@@ -305,6 +305,7 @@
 ### Custom Client 样例
 
 > 一下片断来自项目代码里面的文件：example / cn.jpush.api.examples.DeviceExample
+
 ```Java
     public static void testCustomClient() {
 		ClientConfig config = ClientConfig.getInstance();