update readme

Author: CarGuo

README.md

@@ -80,7 +80,7 @@
 
 ## 编译运行流程
 
-1、配置好Flutter开发环境(目前Flutter SDK 版本 **1.17.1**)，可参阅 [【搭建环境】](https://flutterchina.club)。
+1、配置好Flutter开发环境(目前Flutter SDK 版本 **1.20.1**)，可参阅 [【搭建环境】](https://flutterchina.club)。
 
 2、clone代码，执行`Packages get`安装第三方包。(因为某些不可抗力原因，国内可能需要设置代理: [代理环境变量](https://flutterchina.club/setup-windows/))
 
@@ -104,7 +104,7 @@
 
 ### 4、运行之前请注意下
 
->### 1、本地 Flutter SDK 版本 1.17 ； 2、是否执行过 `flutter pub get`；3、 网络等问题参考: [如果出现登陆失败或者请求失败 ](https://github.com/CarGuo/gsy_github_app_flutter/issues/643)
+>### 1、本地 Flutter SDK 版本 1.20 ； 2、是否执行过 `flutter pub get`；3、 网络等问题参考: [如果出现登陆失败或者请求失败 ](https://github.com/CarGuo/gsy_github_app_flutter/issues/643)
 
 
 ### 下载
@@ -149,7 +149,7 @@
 
 ### 第三方框架
 
->当前 Flutter SDK 版本 1.17.1
+>当前 Flutter SDK 版本 1.20.1
 
 | 库                          | 功能             |
 | -------------------------- | -------------- |

README_EN.md

@@ -43,7 +43,7 @@ With the use and feedback of the project, will user experience and function opti
 
 ### Operation instructions
 
-1. Configure the Flutter development environment (Tag of the current version of Flutter SDK  **1.17.1** ).
+1. Configure the Flutter development environment (Tag of the current version of Flutter SDK  **1.20.1** ).
 
 2. Clone code, execute `Packages get'to install third-party packages.
 
@@ -68,7 +68,7 @@ With the use and feedback of the project, will user experience and function opti
 
 4、Be careful
 
->### Local Flutter SDK version  1.17.1 or more. 2. Does the third-party package version in pubspec. yaml correspond to the third-party package version in pubspec. lock?
+>### Local Flutter SDK version  1.20.1 or more. 2. Does the third-party package version in pubspec. yaml correspond to the third-party package version in pubspec. lock?
 
 ### Download
 
@@ -107,7 +107,7 @@ With the use and feedback of the project, will user experience and function opti
 
 ### Third-party framework
 
->Current Flutter SDK version **1.17.1**
+>Current Flutter SDK version **1.20.1**
 
 | 库                          | 功能             |
 | -------------------------- | -------------- |