JsZip version

Heya, we've been using this library for a while now and it works fine. I've been looking into npm warnings today and figured that you depend on jszip@3.1.5 which requires core-js@<3 which is deprecated and unmaintained. Starting with jszip@3.2.0 they removed the core-js dependency alltogether which is even better. Would you mind updating your jszip to at least v3.2.0?