fix: undo c# 8 syntax for using statements

Author: maurei

src/JsonApiDotNetCore/Builders/JsonApiApplicationBuilder.cs

@@ -96,19 +96,23 @@ public void ConfigureMvc()
         /// </summary>
         public void AddResourceGraph(Type dbContextType, Action<IResourceGraphBuilder> configureResources)
         {
-            using var intermediateProvider = _services.BuildServiceProvider();
-            AutoDiscoverResources(_serviceDiscoveryFacade);
-            AddResourcesFromDbContext(dbContextType, intermediateProvider, _resourceGraphBuilder);
-            UserConfigureResources(configureResources, _resourceGraphBuilder);
-            _services.AddSingleton(_resourceGraphBuilder.Build());
+            using (var intermediateProvider = _services.BuildServiceProvider())
+            {
+                AutoDiscoverResources(_serviceDiscoveryFacade);
+                AddResourcesFromDbContext(dbContextType, intermediateProvider, _resourceGraphBuilder);
+                UserConfigureResources(configureResources, _resourceGraphBuilder);
+                _services.AddSingleton(_resourceGraphBuilder.Build());
+            }
         }
 
         public void ConfigureAutoDiscovery(Action<IServiceDiscoveryFacade> configureAutoDiscovery)
         {
-            using var intermediateProvider = _services.BuildServiceProvider();
-            _serviceDiscoveryFacade = intermediateProvider.GetRequiredService<IServiceDiscoveryFacade>();
-            _resourceGraphBuilder = intermediateProvider.GetRequiredService<IResourceGraphBuilder>();
-            RegisterDiscoverableAssemblies(configureAutoDiscovery, _serviceDiscoveryFacade);
+            using (var intermediateProvider = _services.BuildServiceProvider())
+            {
+                _serviceDiscoveryFacade = intermediateProvider.GetRequiredService<IServiceDiscoveryFacade>();
+                _resourceGraphBuilder = intermediateProvider.GetRequiredService<IResourceGraphBuilder>();
+                RegisterDiscoverableAssemblies(configureAutoDiscovery, _serviceDiscoveryFacade);
+            }
         }
 
         private void RegisterDiscoverableAssemblies(Action<IServiceDiscoveryFacade> configureAutoDiscovery, IServiceDiscoveryFacade serviceDiscoveryFacade)