I have a "cookie" svg with a class of "cookie" , I want the cookie to start from origin and move to -20 and then move to 0 and them move to 20 and them move to 0, and I want it to do it infinite time , I am apparently using GSAP to do it using timeline, but can't figure out how to do it

tl.fromTo(".cookie", { y: 0 }, { y: 20 });
tl.fromTo(".cookie", { y: 20 }, { y: -20 });
tl.fromTo(".cookie", { y: -20 }, { y: 0 });

this code does the work but for one time only, But I want to do it infinite time so Please Help!!