add new package magnetometer_broadcaster to change log

Author: christianrauch

doc/release_notes.rst

@@ -54,3 +54,7 @@ steering_controllers_library
 *****************************
 * Parameter ``tf_frame_prefix`` added with the similar functionality to other controllers. (`#2080 <https://github.com/ros-controls/ros2_controllers/pull/2080>`_).
 * Set odometry service added to be used at runtime. (`#2244 <https://github.com/ros-controls/ros2_controllers/pull/2244>`_).
+
+magnetometer_broadcaster
+************************
+New package to broadcast ``sensor_msgs/msg/MagneticField`` from state interfaces defined by the ``semantic_components::MagneticFieldSensor``.