use windows tests badge

README.md

 ![Wechaty](https://raw.githubusercontent.com/zixia/wechaty/master/image/wechaty-logo-en.png)
-# Wechaty [![Linux Circle CI](https://circleci.com/gh/zixia/wechaty.svg?style=svg)](https://circleci.com/gh/zixia/wechaty) [![Linux Build Status](https://travis-ci.org/zixia/wechaty.svg?branch=master)](https://travis-ci.org/zixia/wechaty) [![Win32 Build status](https://ci.appveyor.com/api/projects/status/60fgkemki7e6upb9?svg=true)](https://ci.appveyor.com/project/zixia/wechaty)
+# Wechaty [![Linux Circle CI](https://circleci.com/gh/zixia/wechaty.svg?style=svg)](https://circleci.com/gh/zixia/wechaty) [![Linux Build Status](https://travis-ci.org/zixia/wechaty.svg?branch=master)](https://travis-ci.org/zixia/wechaty) [![Win32 Build status](https://img.shields.io/appveyor/ci/zixia/wechaty/master.svg?label=Windows%20Tests)](https://ci.appveyor.com/project/zixia/wechaty)
 
 Connecting ChatBots.