how to upgrade dart sdk code example
Example 1: dart update
C:\> choco upgrade dart-sdk
Example 2: set dart sdk from android studio
1- File>> Settings (ctrl+alt+s) >>Languages and Frameworks -> Dart
2- Check "Enable Dart support for the project..."
In "Dart SDK path" click in "..." and navigate to flutter SDK directory
.../flutter/bin/cache/dart-sdk/bin
3- Apply >>ok
Example 3: dart update
C:\> choco install dart-sdk