SDL_joystick: add Austgame adapter to gamecube devices

"Austgame GameCube to USB converter" is an GameCube-to-USB adapter.

src/joystick/SDL_joystick.c

@@ -494,6 +494,7 @@ static Uint32 initial_gamecube_devices[] = {
     MAKE_VIDPID(0x0079, 0x1846), // DragonRise GameCube Controller Adapter
     MAKE_VIDPID(0x057e, 0x0337), // Nintendo Wii U GameCube Controller Adapter
     MAKE_VIDPID(0x057e, 0x2073), // Nintendo Switch 2 NSO GameCube Controller
+    MAKE_VIDPID(0x05e3, 0x0681), // Austgame GameCube to USB convertor
     MAKE_VIDPID(0x0926, 0x8888), // Cyber Gadget GameCube Controller
     MAKE_VIDPID(0x0e6f, 0x0185), // PDP Wired Fight Pad Pro for Nintendo Switch
     MAKE_VIDPID(0x1a34, 0xf705), // GameCube {HuiJia USB box}