fix: Change BookingSystem.AspNetCore.Helpers to BookingSystem.AspNetFramework.Helpers

Author: Reikyo

Examples/BookingSystem.AspNetFramework/Stores/FacilityStore.cs

@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
-using BookingSystem.AspNetCore.Helpers;
+using BookingSystem.AspNetFramework.Helpers;
 using OpenActive.DatasetSite.NET;
 using OpenActive.FakeDatabase.NET;
 using OpenActive.NET;