Fix build error due to Editor specific code

Assets/Scripts/Game/Pickup.cs

@@ -27,6 +27,8 @@ public class Pickup : MonoBehaviour
         string className = this.GetType().ToString();
         GUI.color = Color.blue;
 
+        #if UNITY_EDITOR
             UnityEditor.Handles.Label(transform.position, className);
+        #endif
     }
 }