我正在关注 Flutter 入门教程,但是 运行 get package 时出现错误

I'm following getting started with Flutter tutorials,but while running get package it gets me error

我正在开始学习 Flutter 教程,但是 运行 获取包时出现以下错误

> C:\Users\pacif\Desktop\flutter\bin\flutter.bat --no-color packages upgrade
> Running "flutter packages upgrade" in flutter_app...            
> Error on line 26, column 8 of pubspec.yaml: Invalid version constraint: > Could not parse version "flutter". Unknown text at "flutter".
>   sdk: flutter
>        ^^^^^^^

pub upgrade failed (65) Process finished with exit code 65

C:\Users\pacif\Desktop\flutter\bin\flutter.bat --no-color packages upgrade

Running "flutter packages upgrade" in flutter_app...
Error on line 26, column 8 of pubspec.yaml: Invalid version constraint: > Could not parse version "flutter". Unknown text at "flutter". sdk:flutter

删除多余的Space