Former featherweight champion  Ilia Topuria and former lightweight titleholder  Charles Oliveira will fight for the vacant lightweight championship in the UFC 317 main event on June 28. The fight promotion made the announcement on Tuesday.  Islam Makhachev vacated the 155-pound championship to move up to the welterweight division to pursue a second divisional title. He’s expected to be the first opponent for newly crowned champion  Jack Della Maddalena .   Topuria (16-0) defended the 145-pound title in his last fight, defeating former champion  Max Holloway via knockout. He became the first fighter to KO the Hawaiian