games/libretro-gambatte: Update 0.20250918 => 0.20260515
Commit log: https://github.com/libretro/gambatte-libretro/compare/0092232a0aaef0ded0ead1c2003ccf7a85ccdfc0...3262c2aa4adae8dba4f6d51cdd931c15cb11569f
PR: 296392 Approved by: osa, vvd (Mentors, implicit)