chore(raw_vehicle_cmd_converter): add maintainer (autowarefoundation#8671)

Signed-off-by: kosuke55 <kosuke.tnp@gmail.com>

Author: kosuke55

vehicle/autoware_raw_vehicle_cmd_converter/package.xml

@@ -8,6 +8,9 @@
   <maintainer email="taiki.tanaka@tier4.jp">Tanaka Taiki</maintainer>
   <maintainer email="makoto.kurihara@tier4.jp">Makoto Kurihara</maintainer>
   <maintainer email="sho.iwasawa.2@tier4.jp">Sho Iwasawa</maintainer>
+  <maintainer email="kosuke.takeuchi@tier4.jp">Kosuke Takeuchi</maintainer>
+  <maintainer email="takayuki.murooka@tier4.jp">Takayuki Murooka</maintainer>
+  <maintainer email="kyoichi.sugahara@tier4.jp">Kyoichi Sugahara</maintainer>
 
   <license>Apache License 2.0</license>