fix: Reversed the tile stacking order to fix tiles being layered impr…

…operly

Assets/LDtkUnity/Editor/Builders/TilemapTilesBuilder.cs

@@ -56,7 +56,7 @@ public int GetNextCellZ(Vector3Int cell)
                 return 0;
             }
 
-            _depth[cell] -= 1;
+            _depth[cell] += 1;
             return _depth[cell];
         }