These webpack issues are getting out of hand, so I made a little demo to help you get started.
But first, have you considered not importing GSAP? I would suggest using a CDN instead as your app will load much faster since it's not included in the bundle and can be pulled directly from the user's browser cache. GSAP is available on both cdnjs and jsDelivr. JsDelivr is kind of unique in that you can bundle all your files up in a single HTTP request!