Upgrade dart SDK version range to support 2.1.0

[java-james]

Flutter beta channel has bumped to Dart SDK 2.1.0.
Flutter recommends developing against the beta channel.
Can we upgrade the SDK range in pubspec.yaml to >=1.20.1 <=2.1.0support this please.

[Rahiche]

thanks for the PR
merged

[juliovedovatto]

@Rahiche could you update the badge package at https://pub.dartlang.org/packages/badge#-versions-tab- please?

I'm not able to run my flutter project due the package hosted there still restraining SDK version.

Could you bump the package version to 0.0.3 with the fix of the sdk environement?

flutter packages get
Running "flutter packages get" in grocery_list...
The current Dart SDK version is 2.1.0-dev.3.1.flutter-760a9690c2.

Because grocery_list depends on badge 0.0.2 which requires SDK version >=1.20.1 <=2.0.0, version solving failed.
pub get failed (1)

I know I can put directly the github url in my pubspec.yaml, but I would like to use pub.dartlang.org to install/update my packages.

thanks!

[Rahiche]

done and i really appreciate your work
thank you