By Matt Hladik Dallas Cowboys defensive coordinator Dan Quinn’s transformation of a unit that was one of the worst in the league in 2020 was a major reason why “America’s Team” reached the playoffs in 2021. Today, the Pro Football Writers of America honored Quinn for his performance, naming him the 2021 Assistant Coach of the Year. The news caps off what was a strong first year in Dallas for the former Atlanta Falcons head coach. It also comes on the day Quinn announced he’d be removing his name from consideration for head coaching positions around the NFL and returning to the Cowboys for anot…