CMT announced its second round of performers for the 2018 CMT Music Awards at Nashville’s Bridgestone Arena on June 6. The new additions include Carrie Underwood, Dan + Shay, Florida Georgia Lina, Jason Aldean, Little Big Town, Backstreet Boys, Dierks Bentley with Brothers Osborne, and Darius Rucker with Jason Aldean, Luke Bryan and Charles Kelley.…