fix: shift decider README (autowarefoundation#750) (autowarefoundatio…

…n#128)

* fix topic name described in README

* fix readme.md

Signed-off-by: wep21 <border_goldenmarket@yahoo.co.jp>

Co-authored-by: Taichi Hirano <85976747+td12321@users.noreply.github.com>

control/shift_decider/README.md

@@ -43,9 +43,9 @@ stop
 
 ### Output
 
-| Name                | Type                                           | Description                        |
-| ------------------- | ---------------------------------------------- | ---------------------------------- |
-| `~output/shift_cmd` | `autoware_auto_vehicle_msgs::msg::GearCommand` | Gear for drive forward / backward. |
+| Name               | Type                                           | Description                        |
+| ------------------ | ---------------------------------------------- | ---------------------------------- |
+| `~output/gear_cmd` | `autoware_auto_vehicle_msgs::msg::GearCommand` | Gear for drive forward / backward. |
 
 ## Parameters