asketch2sketch plugin doesn't work with Sketch v64
due to changes here:
abynim/Sketch-Headers@ce52485#diff-2e6721c2d801e437b6678cce78235955

It was already fixed in [sketchapp-json-plugin](https://github.com/darknoon/sketchapp-json-plugin) (which is a dependency in html-sketchapp) but not published to npm yet.
https://github.com/darknoon/sketchapp-json-plugin/issues/16

error from mac console:
<img width="1260" alt="Screenshot 2020-04-01 at 09 43 18" src="https://user-images.githubusercontent.com/1231144/78111684-50ef4680-73fd-11ea-8b4b-6b3de5ec66cf.png">

