如下是查询flutter的版本，发现对应的dart才是2.14，但现在dart最新版本已经是v3.28.0了，我能单独升级dart到最新版吗？
MacBook-Pro flutter_template % /Users/liu/flutter/bin/flutter --version
Flutter 2.5.2 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 3595343e20 (7 weeks ago) • 2021-09-30 12:58:18 -0700
Engine • revision 6ac856380f
Tools • Dart 2.14.3
