Federal authorities are investigating sex-trafficking allegations against Vince McMahon, according to a new report. The founder of World Wrestling Entertainment, or WWE, resigned from his roles at parent company TKO last week, a day after a former WWE employee accused him of sexual misconduct. In a 67-page complaint filed in U.S. District Court in Connecticut, Janel Grant alleged that she was required to maintain a sexual relationship with McMahon and submit to his “sexual demands” in return for employment at WWE. Those demands involved alleged acts of“extreme cruelty and degradation,” which e…