Beauty brands, seeking foot traffic and summer-appropriate activations, are now also lining up to get in on the frozen yogurt boom. “[Go Greek] is such an L.A. staple. We all know when you go to L.A., you’ve got to get an Erewhon smoothie, and you have to go to Go Greek,” said Caroline Joseph, senior brand and marketing manager at skin-care brand Korres, of the frozen yogurt chain Go Greek, which opened its first New York City location in Noho in April.