22-year-old Greta Kline started puting intriguing song sketches online when she was in her teens, slowly amassing a cult following before releasing her promising debut Zentropy in 2014. On Next Thing, Kline, who records with a roving group of collaborators under the moniker Frankie Cosmos, moves from the lonesome bedroom to the cramped garage, updating her cloistered lo-fi aesthetic with a…