Add catalogitem update endpoint to public api (#418)

* Initial update endpoint working

* Updated CatalogItem to support more updates; added tests

* Got MediatR domain events working to check for duplicate item names

* Adding reference link

* Remove domain events spike code

* clean up usings

src/Web/Services/CatalogItemViewModelService.cs

@@ -18,7 +18,7 @@ namespace Microsoft.eShopWeb.Web.Services
         public async Task UpdateCatalogItem(CatalogItemViewModel viewModel)
         {
             var existingCatalogItem = await _catalogItemRepository.GetByIdAsync(viewModel.Id);
-            existingCatalogItem.Update(viewModel.Name, viewModel.Price);
+            existingCatalogItem.UpdateDetails(viewModel.Name, existingCatalogItem.Description, viewModel.Price);
             await _catalogItemRepository.UpdateAsync(existingCatalogItem);
         }
     }