To add the Flavors to the application, place these files in a directory called flavor at the root of the project.

cd flavor
chmod +x flavor.sh && ./flavor.sh "App Flavor" # App Name

to execute the flavors:

flutter run
flutter run --dart-define=DEFINE_APP_NAME='[QA] App Flavor' --dart-define=DEFINE_APP_SUFFIX=.qa
flutter run --dart-define=DEFINE_APP_NAME='[DEV] App Flavor' --dart-define=DEFINE_APP_SUFFIX=.dev