Construct superstructure sender

That lets us actually control the superstructure!

Change-Id: I48b96d348ba65aee2faa6fb72bea36bef60ad296
diff --git a/y2020/actors/autonomous_actor.cc b/y2020/actors/autonomous_actor.cc
index c59aa7a..d3d8570 100644
--- a/y2020/actors/autonomous_actor.cc
+++ b/y2020/actors/autonomous_actor.cc
@@ -34,6 +34,9 @@
           event_loop->MakeSender<
               ::frc971::control_loops::drivetrain::LocalizerControl>(
               "/drivetrain")),
+      superstructure_goal_sender_(
+          event_loop->MakeSender<control_loops::superstructure::Goal>(
+              "/superstructure")),
       joystick_state_fetcher_(
           event_loop->MakeFetcher<aos::JoystickState>("/aos")),
       path_fetcher_(event_loop->MakeFetcher<y2020::vision::GalacticSearchPath>(