Update to make the walking-controller work

See robotology/gz-sim-yarp-plugins#122 (comment)

example.world

@@ -1,12 +1,15 @@
 <?xml version="1.0"?>
 
-<sdf version="1.7">
+<sdf version="1.11">
     <!-- Example world used to try ergocub in Gazebo -->
     <world name="tutorial_controlboard">
         <physics name="1ms" type="ignored">
             <max_step_size>0.001</max_step_size>
             <real_time_factor>1.0</real_time_factor>
-            <!-- <max_contacts>8</max_contacts> -->
+            <!-- <max_contacts>4</max_contacts> -->
+            <!-- <dart>
+                <collision_detector>ode</collision_detector>
+            </dart> -->
         </physics>
         <plugin
             filename="gz-sim-physics-system"
@@ -32,12 +35,16 @@
             filename="gz-sim-scene-broadcaster-system"
             name="gz::sim::systems::SceneBroadcaster">
         </plugin>
+        <plugin
+            filename="gz-sim-contact-system"
+            name="gz::sim::systems::Contact">
+        </plugin>
 
         <!-- YARP CLOCK -->
-        <!-- <plugin
+        <plugin
             filename="gz-sim-yarp-clock-system"
             name="gzyarp::Clock">
-        </plugin> -->
+        </plugin>
 
         <light type="directional" name="sun">
             <cast_shadows>true</cast_shadows>

install/share/ergoCub/robots/ergoCubGazeboV1_1/model.sdf

@@ -4475,12 +4475,6 @@
     <yarpConfigurationFile>model://ergoCub/conf/gazebo_ergocub_waist_inertial.ini</yarpConfigurationFile>
     </plugin> -->
 
-    <!-- CLOCK -->
-    <plugin
-      filename="gz-sim-yarp-clock-system"
-      name="gzyarp::Clock">
-    </plugin>
-
     <!-- IMUs -->
 
     <plugin name="gzyarp::Imu" filename="gz-sim-yarp-imu-system">

setup.sh

@@ -1,3 +1,4 @@
 export GZ_SIM_RESOURCE_PATH=${GZ_SIM_RESOURCE_PATH}:/home/acroci/ergocub_ws/install/share/
 export YARP_ROBOT_NAME="ergoCubGazeboV1_1"
 export YARP_DATA_DIRS=${YARP_DATA_DIRS}:/home/acroci/ergocub_ws/install/share/ergoCub
+# export YARP_CLOCK=/clock