update README.md.

Signed-off-by: JustryDeng <m13548417409@163.com>

README.md

@@ -84,7 +84,7 @@
   # linux
   java -jar class-winter-core-2.7.2.jar k1='v1' k2='v2'
   # windows
-  java -jar class-winter-core-2.7.20.jar k1="v1" k2="v2"
+  java -jar class-winter-core-2.7.2.jar k1="v1" k2="v2"
   ```
 
 ## <font  face="幼圆" color = "#3399EA" >加密参数</font>