Join spinner before exit (#717)

* Join spinner before exit

* Call join() before shutdown()

---------

Co-authored-by: Sebastian Jahr <[email protected]>

Author: todoubaba

doc/how_to_guides/pilz_industrial_motion_planner/src/pilz_move_group.cpp

@@ -178,6 +178,7 @@ int main(int argc, char* argv[])
   }
 
   // Shutdown ROS
+  spinner.join();
   rclcpp::shutdown();
   return 0;
 }