added cleanup call to prevent tmp_dir from warning when garbage colle…

…cting

gymnasium_robotics/envs/maze/maze_v4.py

@@ -423,3 +423,7 @@ def update_target_site_pos(self, pos):
         """Override this method to update the site qpos in the MuJoCo simulation
         after a new goal is selected. This is mainly for visualization purposes."""
         raise NotImplementedError
+
+    def __del__(self):
+        self.tmp_dir.cleanup()
+        super().__del__()