Fix Quill buttons in Safari 14

Steps to reproduce :

1. create a Note document in Safari 14.1
2. type some text in the Quill editor
3. select the text
4. click the Bold button
5. observe that nothing happens
6. however if you start typing some text now, you'll observe that the text is in Bold

The same scenario (step 5) works with Chrome 90.

Other features like Italics or Image upload does not work either.

I've noticed that Nuxeo is using version 2.0.0-dev3 whereas quilljs.com, where the same scenario works, uses version 1.3.6 => is it related?

According to Quill, only Safari 12 and 13 are compatible : https://github.com/quilljs/quill/#readme