By Tzvi Machlin Playoff success for the Dallas Cowboys has been limited since the mid-1990s and starting quarterback Dak Prescott is just 1-3 in the postseason. But Colin Cowherd thinks he knows how Dak can get his second playoff win. On Friday’s edition of The Herd, Cowherd said that the key to Dallas winning in the postseason is having a strong performance from their rushing attack with Dak playing “complementary” football. Cowherd believes that Dallas’ chances of doing so are good since they’re unlikely to face a strong run defense the playoffs. “We know there’s a way for the Cowboys to win…