Not that it has anything to do with when the new movie takes place, since, according to the show's official website, West Side Story takes place in the mid-1950's, definitively, but I'm sure Brody was referring to what Tony Kushner said in this article:
https://www.vanityfair.com/hollywood/2018/10/west-side-story-remake-spielberg-tony-kushner
The playwright said that the new adaptation will not be an exact retelling of Robert Wise’s iconic 1961 film, starring Natalie Wood, Richard Beymer, Rita Moreno, and George Chakiris. Instead, Spielberg’s version will turn back to the original 1957 Broadway musical written by Arthur Laurents, with music by Leonard Bernstein and lyrics by Stephen Sondheim.
“It’s not a straightforward remake [of the movie], but it’s definitely the Jets and the Sharks. It’s New York City. I think people will find a new way to love the story and to love the songs through our interpretation,” said Kushner on the red carpet. “The way I approached it and the way Steven is approaching it is using the great text—the Leonard Bernstein score, which is arguably the most beautiful score ever written for musical theater, and Arthur Laurents’s original book is a masterpiece. And we started building from that.”