Just hours before news broke that Lena Dunham will pen another HBO show, the “Girls” creator-star and a half-dozen gal pals were at Victor’s Cafe, toasting her success with margaritas and mojitos Wednesday night. HBO announced Thursday that it optioned a memoir, “All Dressed Up and Nowhere To Go,” by Bergdorf Goodman personal shopper Betty Halbreich, who has styled dames since the ’70s. Dunham and “Girls” writer Jenni Konner will pen the pilot.