Add release notes

Author: saikishor

doc/release_notes.rst

@@ -14,6 +14,9 @@ controller_manager
 hardware_interface
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 * The ``prepare_command_mode_switch`` and ``perform_command_mode_switch`` methods will now only receive the start/stop interfaces that belong to the hardware component instead of everything (`#2120 <https://github.com/ros-controls/ros2_control/pull/2120>`_)
+* The hardware interface is now treated similarly as ERROR, when a hardware component returns ERROR on the read cycle (`#2334 <https://github.com/ros-controls/ros2_control/pull/2334>`_).
+* The controllers are now deactivated when a hardware component returns DEACTIVATE on the write cycle. The parameter ``deactivate_controllers_on_hardware_self_deactivate`` is added to control this behavior temporarily. It is recommended to set this parameter to true in order to avoid controllers to use inactive hardware components and to avoid any unexpected behavior. This feature parameter will be removed in future releases and will be defaulted to true (`#2334 <https://github.com/ros-controls/ros2_control/pull/2334>`_ & `#2501 <https://github.com/ros-controls/ros2_control/pull/2501>`_).
+* The controllers are not allowed to be activated when the hardware component is in INACTIVE state. The parameter ``allow_controller_activation_with_inactive_hardware`` is added to control this behavior temporarily. It is recommended to set this parameter to false in order to avoid controllers to use inactive hardware components and to avoid any unexpected behavior. This feature parameter will be removed in future releases and will be defaulted to false (`#2347 <https://github.com/ros-controls/ros2_control/pull/2347>`_).
 
 ros2controlcli
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