Rebecca Rubin Film and Media ReporterRobert De Niro has joined the cast of “About My Father,” an upcoming film that’s loosely based on the life of standup comic Sebastian Maniscalco.De Niro is set to play Maniscalco’s dad Salvo in the movie, reuniting the pair after first appearing together in Martin Scorsese’s mob drama “The Irishman.”In “About My Father,” Sebastian tells his old-school Italian immigrant dad of his plans to propose to his all-American girlfriend, prompting Salvo to insist on