They haven't made it for MAME 0.181 - you can wait four weeks for MAME 0.182 or you can build your own MAME from master if you're really impatient and you get bored with listening to the Toaplan games.
Ah ok i get it now i assumed the cut off point for new code additions was when the next build of MAME was released, im sure most users will be happy to wait a little longer for Sky Robo.