docs(README): fix to Engine example
docs(README): fix to Engine example

Previously the example would throw an exception complaining no provider found for Fuel. It would
also warn of deprecation of the `withAnnotation:` syntax. This fixes both issues.

BlackHC/di.dart,BlackHC/di.dart,dart-archive/di.dart,winstonewert/di.dart,winstonewert/di.dart,Pacane/di.dart,winstonewert/di.dart,Pacane/di.dart,dart-archive/di.dart,dart-archive/di.dart,winstonewert/di.dart,Pacane/di.dart,BlackHC/di.dart,Pacane/di.dart,dart-archive/di.dart,BlackHC/di.dart