mr_lab.world: add another light to avoid person dark shadow

worlds/mr_lab.world

@@ -9,15 +9,17 @@
     
     <light type="directional" name="sun">
       <cast_shadows>true</cast_shadows>
-      <pose>0 0 10 0.2 0.2 0.2</pose>
-      <diffuse>0.8 0.8 0.8 1</diffuse>
-      <specular>0.2 0.2 0.2 1</specular>
-      <attenuation>
-        <range>1000</range>
-        <constant>0.9</constant>
-        <linear>0.01</linear>
-        <quadratic>0.001</quadratic>
-      </attenuation>
+      <pose>0 0 10 0.0 0.0 0.0</pose>
+      <diffuse>0.7 0.7 0.7 1</diffuse>
+      <specular>1 1 1 0</specular>
+      <direction>0.5 0.1 -0.9</direction>
+    </light>
+
+    <light type="directional" name="sun2">
+      <cast_shadows>false</cast_shadows>
+      <pose>0 0 11 0.0 0.0 0.0</pose>
+      <diffuse>0.7 0.7 0.7 1</diffuse>
+      <specular>1 1 1 0</specular>
       <direction>-0.5 0.1 -0.9</direction>
     </light>