更新 README

README.md

@@ -2,6 +2,7 @@
 
 [![Latest Version on Packagist][ico-version]][link-packagist]
 [![Total Downloads][ico-downloads]][link-downloads]
+[![Software License][ico-license]](LICENSE)
 
 所有SDK源文件取自 [支付宝官网](https://docs.open.alipay.com/54/103419/)，原版未改动。
 
@@ -32,11 +33,13 @@ If you discover any security related issues, please email [email protected] in
 - [Haobing Wang][link-author]
 
 
-[ico-version]: https://img.shields.io/packagist/v/miuhr/alipay-sdk.svg?style=flat-square
+[ico-version]: https://img.shields.io/packagist/v/miuhr/alipay-sdk.svg
 [link-packagist]: https://packagist.org/packages/miuhr/alipay-sdk
 
-[ico-downloads]: https://img.shields.io/packagist/dt/miuhr/alipay-sdk.svg?style=flat-square
+[ico-downloads]: https://img.shields.io/packagist/dt/miuhr/alipay-sdk.svg
 [link-downloads]: https://packagist.org/packages/miuhr/alipay-sdk
 
+[ico-license]: https://img.shields.io/badge/license-MIT-brightgreen.svg
+
 [link-author]: https://github.com/haobingwang