Please fix dart pub global activate PROG to generate scripts that use dart pub instead of pub

[RandalSchwartz]

For all the reasons I've mentioned about flutter pub global activate in flutter/flutter#79131, the same is true for dart pub global activate. It might even be the same code.

As pub is being deprecated, replaced with dart pub or flutter pub, this is beginning to affect more people. Most people are using the dart-sdk that is within their flutter-sdk, and adding only the flutter bin to their path, and not the legacy dart-sdk bin into their path. But dart pub global activate creates shell scripts that fall back to pub run if the SDK version has changed. But there's no more pub, so this requires a meticulous re-creating of everything in dart pub global list or face broken apps.

If the flutter fix is fixing the same code, please coordinate. But please make this soon. This breaks tools like dcli as well.

[mkustermann]

/cc @jonasfj

[RandalSchwartz]

Can we please bump this a bit? It's increasingly affecting new installations.

[jonasfj]

Filed #3002

[jonasfj]

Fixed, should ship with Dart 2.14