fix item update api

api/src/Services/ItemService.cs

@@ -31,10 +31,17 @@ public class ItemService {
         return item;
     }
 
-    public async Task<Item> Update(Item item) {
-        db_.Items.Update(item);
+    public async Task<Item?> Update(int id, ItemDto item) {
+
+        Item? oldItem = await db_.Items.FindAsync(id);
+        if(oldItem == null) return oldItem;
+
+        oldItem.Name = item.Name;
+        oldItem.Description = item.Description;
+        oldItem.LastEditedAt = DateTime.UtcNow;
+
         await db_.SaveChangesAsync();
-        return item;
+        return oldItem;
     }
 
     public async Task<bool> Delete(int id) {