It's part of the 3.0 update, I believe. There's a link that lists what comes with the update, and the clothing is listed in the "Other" section of the link. The link is in the first post of this thread, where the 3.0 update is mentioned.

The rewards for events like lucky board aren't usually revealed beforehand. Gotta keep some kind of mystery going for the events, y'know? ^^

I would guess that either Minato or Masked Man will be in there. I don't think both of them will be, but it's always possible I guess. It's also possible the new clothing could be a redeemable reward. Beyond that, there's the usual medium refines, medium threads, charm packs (usually two out of the three, lately it's been the medium refines and charm packs). Either way, I'm pretty sure there will be something new to redeem in the upcoming lucky board.

Just gotta be patient and wait until tomorrow.

Ah, whoops, completely missed the "Redeem Shop" tab shown in the picture for that event, my bad! I assumed Minato/Masked Obito were just used as a theme for that event, but were able to be pieced together/recruited elsewhere. Then yeah, lucky board might not have a new ninja to grab this time around.