Remove SceneManagement, it's not required

The scene is automatically set as dirty when the gui target is

Author: rogerbarton

scripts/Editor/DllManipulatorEditor.cs

@@ -8,8 +8,6 @@
 #endif
 using System.IO;
 using System;
-using UnityEditor.SceneManagement;
-using UnityEngine.SceneManagement;
 
 namespace UnityNativeTool.Internal
 {
@@ -148,7 +146,6 @@ public override void OnInspectorGUI()
             if (GUI.changed)
             {
                 EditorUtility.SetDirty(target);
-                EditorSceneManager.MarkSceneDirty(SceneManager.GetActiveScene());
             }
         }