LAS VEGAS (AP) — Welterweight champions Errol Spence Jr. and Shawn Porter will meet in a unification bout Sept. 28 in Los Angeles. Spence and Porter announced the date and location of their showdown Saturday. Spence (25-0, 21 KOs) holds the IBF 147-pound title, while Porter (30-2-1, 17 KOs) is the...