Keke Palmer is now single. According to People, the American actress and her boyfriend, Darius Jackson, have broken up after two years of dating.   “He’s moved on,” a source told the magazine of the fitness instructor. Reps for the former couple didn’t immediately respond to Page Six’s requests for comment.   The news comes after Jackson publicly shamed Palmer, 29, in July for wearing a sexy outfit to an Usher concert.   The “Nope” star who welcomed her first …