use ros_diff_drive in case name changes

nav2_bringup/nav2_gazebo_spawner/nav2_gazebo_spawner/nav2_gazebo_spawner.py

@@ -78,7 +78,7 @@ def main():
     tree = ET.parse(sdf_file_path)
     root = tree.getroot()
     for plugin in root.iter('plugin'):
-        if 'libgazebo_ros_diff_drive.so' == plugin.get('filename'):
+        if 'ros_diff_drive' in plugin.get('filename'):
             # The only plugin we care for now is 'diff_drive' which is
             # broadcasting a transform between`odom` and `base_footprint`
             break