The “For All Mankind” spinoff “Star City” has made three new additions to its main cast, Variety has learned. Adam Nagaitis (“The Terror,” “Chernobyl,” “The Responder”), Josef Davies (“Andor,” “The Hunt for Raoul Moat,” “Young Wallander”), and Ruby Ashbourne Serkis (“I, Jack Wright,” “Shardlake,” “Becoming Elizabeth”) have all joined the upcoming Apple TV+ alt-history drama. […]