Update jazzy branch for demos (#2463)

Author: christophfroehlich

ros_controls.jazzy.repos

@@ -6,7 +6,7 @@ repositories:
   ros-controls/ros2_control_demos:
     type: git
     url: https://github.com/ros-controls/ros2_control_demos.git
-    version: master
+    version: jazzy
   ros-controls/ros2_controllers:
     type: git
     url: https://github.com/ros-controls/ros2_controllers.git