By Emma Baccellieri Here are the areas where the Yankees, Dodgers and other teams in the postseason picture should look to upgrade. Welcome to the final stretch before the trade deadline. (Remember, the date to know this season is August 2, as July 31 falls on a Sunday.) This year might not have the most overpowering group of trade candidates—at least in the Not-Juan Soto Category—but there’s still plenty of activity to anticipate. Which team will land Luis Castillo? How will a third wild card berth change teams’ calculus? And, per usual, just about everyone could use a little extra bullpen he…