Update ServiceProvider.cs

Author: ENikS

src/ServiceProvider.cs

@@ -57,7 +57,7 @@ public IServiceScope CreateScope()
 
         public static IServiceProvider ConfigureServices(IServiceCollection services)
         {
-            return new ServiceProvider(new UnityContainer().AddNewExtension<MdiExtension>()
+            return new ServiceProvider(new UnityContainer().AddExtension(new MdiExtension())
                                                            .AddServices(services));
         }
 
@@ -81,4 +81,4 @@ private void Dispose(bool mode)
 
         #endregion
     }
-}
+}