Flutter-3: flutter 更新 SDK download

1: flutter sdk download

- 来到flutter 官方网站

- download url: 选择最稳定的版本stable 
https://flutter.dev/docs/development/tools/sdk/releases?tab=macos

2: unzip flutter sdk in the Application

- 将下载flutter sdk 拖入到应用程序中

- 解压flutter sdk

- 配置环境变量bash_profile

- open bash_profile

- add variable path: 
    # Flutter 
    export PATH=$PATH:/Applications/flutter/bin
    
    # Mirror image
    export PUB_HOSTED_URL=https://pub.flutter-io.cn
    export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn

- 这样的话、就可以全局使用flutter命令如：flutter --version; flutter doctor

3: configure iOS environment

- download Xcode：
https://developer.apple.com/download/more/

- drag in Application and unzip it 
    

4: configure Android environment