Replace `AppData\Roaming\Pub\Cache\bin` with `AppData\Local\Pub\Cache\bin` in PATH

[julemand101]

Pub are no longer using the Roaming directory when handling cache and installation of programs. Instead, it have been using Local for some time:

dart-lang/pub#2297
dart-lang/pub#3831

The consequence of this is that installing Dart though Chocolatey does set the wrong path right now and users are therefore needed to manually fixing the PATH after installing a program like e.g. webdev through pub.

[sortie]

Done in 7f5b6d7