Fix build error (CustomBirdTutorial exists in both Everest and SC2020)

Author: maddie480

Triggers/CustomBirdTutorialTrigger.cs

@@ -1,9 +1,8 @@
-using Celeste.Mod.Entities;
-using Celeste.Mod.SpringCollab2020.Entities;
+using Celeste.Mod.SpringCollab2020.Entities;
 using Microsoft.Xna.Framework;
 
 namespace Celeste.Mod.SpringCollab2020.Triggers {
-    [CustomEntity("SpringCollab2020/CustomBirdTutorialTrigger")]
+    [Mod.Entities.CustomEntity("SpringCollab2020/CustomBirdTutorialTrigger")]
     class CustomBirdTutorialTrigger : Trigger {
         private string birdId;
         private bool showTutorial;