The International Brotherhood of Teamsters said Wednesday that negotiations over a new contract with shipping giant UPS had “collapsed,” increasing the odds of a massive strike next month.The two sides still have time to reach a new agreement and avoid a work stoppage, with the current contract in effect until July 31. But the Teamsters had said they wanted a new tentative deal in place by the end of the July 4 holiday to give workers time to digest and vote on it.On Wednesday morning, the Teamsters accused UPS of refusing to give them a “last, best and final offer” by that deadline. “This multibillion-dollar corporation has plenty to give American workers ― they just don’t want to,” Sean O’Brien, the union’s president, said in a statement. “UPS had a choice to make, and they have clearly...