add velocity_controllers dependency to world_handler

[MizuhoAOKI]

sudo apt-get install -y ros-noetic-velocity-controllers is needed to use JointVelocityController plugin.

edit package.xml for installing it with rosdep.
https://github.com/MizuhoAOKI/nullspace_mpc/blob/main/src/simulation/gazebo/world_handler/package.xml#L13-L41

[MizuhoAOKI]

It worked, but I am not sure if three "velocity_controller" sentence are needed.

<?xml version="1.0"?>
<package format="2">
  <name>world_handler</name>
  <version>0.0.0</version>
  <description>make gazebo world and spawn a 4wids vehicle</description>

  <!-- maintainer -->
  <maintainer email="mizuhoaoki1998@gmail.com">Mizuho Aoki</maintainer>

  <!-- license -->
  <license>MIT</license>

  <!-- dependencies -->
  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_depend>tf2</build_depend>
  <build_depend>tf2_geometry_msgs</build_depend>
  <build_depend>tf2_ros</build_depend>
  <build_depend>gazebo_ros</build_depend>
  <build_depend>gazebo_ros_control</build_depend>
  <build_depend>ros_control</build_depend>
  <build_depend>ros_controllers</build_depend>
  <build_depend>velocity_controllers</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <build_export_depend>tf2</build_export_depend>
  <build_export_depend>tf2_geometry_msgs</build_export_depend>
  <build_export_depend>tf2_ros</build_export_depend>
  <build_export_depend>gazebo_ros</build_export_depend>
  <build_export_depend>gazebo_ros_control</build_export_depend>
  <build_export_depend>ros_control</build_export_depend>
  <build_export_depend>ros_controllers</build_export_depend>
  <build_export_depend>velocity_controllers</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>std_msgs</exec_depend>
  <exec_depend>tf2</exec_depend>
  <exec_depend>tf2_geometry_msgs</exec_depend>
  <exec_depend>tf2_ros</exec_depend>
  <exec_depend>gazebo_ros</exec_depend>
  <exec_depend>gazebo_ros_control</exec_depend>
  <exec_depend>ros_control</exec_depend>
  <exec_depend>ros_controllers</exec_depend>
  <exec_depend>velocity_controllers</exec_depend>

  <!-- export gazebo asset paths -->
  <exec_depend>gazebo_ros</exec_depend>
  <export>
    <gazebo_ros gazebo_media_path="${prefix}/world" />
  </export>

</package>