pub command in dart and flutter

[simonjtyler]

With a lot of new Dart users coming from the flutter space, the details on how to run the tests etc. might need to be updated.

E.g., replace/give alternatives to pub run test with flutter pub run test or dart run test in https://exercism.io/tracks/dart/tests

From the current docs: dart.dev/tools/pub/cmd

Flutter note: If you’re using the Flutter SDK, don’t use the pub command directly. Instead use the flutter pub command, as described in Using packages on the Flutter website.

And I think the separate pub command will be depreciated soon anyway: dart.dev/tools/dart-tool

Version note: Before Dart 2.10, the dart command was used only to run the Dart VM. You can still use it that way, but now the command has more functionality. Over time, we expect the dart command to replace most existing commands in the Dart SDK.

[SleeplessByte]

Can you also open this on https://github.com/exercism/dart? The changed needs to happen there (docs folder).