By Evan Nachimson The most decorated U.S. gymnast in history is dropping a new line of activewear just in time for fall. When she’s not being awarded the Presidential Medal of Freedom or winning the most medals of any American gymnast in history, Simone Biles is creating new activewear with Athleta. Her partnership with the athleisure company began during the lead-up to the Tokyo Olympics last summer. Biles’s first collab, a limited-edition “In Your Element” hoodie, was a major smash when it dropped last fall. This spring Biles partnered with Athleta Girl for her first collection specifically …