Provide default joystick_reader goal

Change-Id: I105ea882d3b1c3281da13b9434f1f32a248740ec
Signed-off-by: James Kuszmaul <jabukuszmaul@gmail.com>
diff --git a/y2022/joystick_reader.cc b/y2022/joystick_reader.cc
index a911e4b..cc2c6e9 100644
--- a/y2022/joystick_reader.cc
+++ b/y2022/joystick_reader.cc
@@ -258,6 +258,8 @@
 
     if (data.IsPressed(kFire)) {
       fire = true;
+      // Provide a default turret goal.
+      turret_pos = 0.0;
     }
 
     {