update

AllPay_Integration_Specification_EN.md

@@ -1,4 +1,4 @@
-# GoAllPay Integration Specification V5.0.0
+# GoAllPay Integration Specification V5.1.0
 [Shanghai GoAllPay Technology Co., Ltd.](https://www.goallpayx.com)
 
 * Version: English V5.1.0