drawer opening update for noetic

After this minor change, drawer opening worked with the
following command.

$ roslaunch stretch_demos open_drawer.launch

The following persistent warning would be good to resolve.

[ WARN] [1622728896.394958823]: Could not obtain transform from imu_mobile_base to base_link. Error was Could not find a connection between 'base_link' and 'imu_mobile_base' because they are not part of the same tree.Tf has two or more unconnected trees.

stretch_demos/nodes/open_drawer

@@ -1,6 +1,6 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
-from __future__ import print_function
+#from __future__ import print_function
 
 from sensor_msgs.msg import JointState
 from geometry_msgs.msg import Twist