Switch to using ros_gz_sim to run Gazebo (#344)

Signed-off-by: Luca Della Vedova <lucadv@intrinsic.ai>

Author: luca-della-vedova

rmf_demos_gz/launch/simulation.launch.xml

@@ -17,10 +17,13 @@
   <let name="gz_headless" unless="$(var headless)" value="" />
 
   <!-- TODO(luca) Remove the manual concatenation of GZ_SIM_RESOURCE_PATH and just use environment hooks -->
-  <executable cmd="gz sim $(var gz_headless) -r -v 3 $(var world_path) -z $(var sim_update_rate)" output="both">
-    <env name="GZ_SIM_RESOURCE_PATH" value="$(env GZ_SIM_RESOURCE_PATH):$(var model_path)" />
-    <env name="MENGE_RESOURCE_PATH" value="$(var menge_resource_path)"/>
-  </executable>
+  <group>
+    <set_env name="GZ_SIM_RESOURCE_PATH" value="$(env GZ_SIM_RESOURCE_PATH):$(var model_path)" />
+    <set_env name="MENGE_RESOURCE_PATH" value="$(var menge_resource_path)"/>
+    <include file="$(find-pkg-share ros_gz_sim)/launch/gz_sim.launch.py">
+      <arg name="gz_args" value="$(var gz_headless) -r -v 3 $(var world_path) -z $(var sim_update_rate)"/>
+    </include>
+  </group>
 
   <!-- ros_gz bridge for simulation clock -->
   <node pkg="ros_gz_bridge" exec="parameter_bridge"

rmf_demos_gz/package.xml

@@ -18,9 +18,9 @@
   <exec_depend>teleop_twist_keyboard</exec_depend>
   <exec_depend>launch_xml</exec_depend>
   <exec_depend>ros2launch</exec_depend>
-  <exec_depend>gz_sim_vendor</exec_depend>
 
   <exec_depend>ros_gz_bridge</exec_depend>
+  <exec_depend>ros_gz_sim</exec_depend>
 
   <export>
     <build_type>ament_cmake</build_type>