fix: Fixed configureDependencies return type (#158)

Author: utpal-barman

lib/injection/dependencies.dart

@@ -7,6 +7,6 @@ class DependencyManager {
     injector.registerLazySingleton<AppFlavor>(() => flavor);
     // ignore: unnecessary_lambdas
     injector.registerLazySingleton<AppRouter>(() => AppRouter());
-    configureDependencies();
+    return configureDependencies();
   }
 }

lib/injection/injector.dart

@@ -2,7 +2,7 @@ import 'package:flutter_template/injection/injector.config.dart';
 import 'package:get_it/get_it.dart';
 import 'package:injectable/injectable.dart';
 
-GetIt injector = GetIt.instance;
+GetIt injector = GetIt.I;
 
 @injectableInit
-void configureDependencies() => injector.init();
+Future<void> configureDependencies() => injector.init();