Conversion to Tailwind 1.7

[chrisvidal]

I've made a fork of the theme and convert it to Tailwind 1.7, available code here https://github.com/Voilaah/oc-mall-theme

JS and SCSS compilation is ok, however, at this stage I didn't yet test the theme itself.

[tobias-kuendig]

Thank you @chrisvidal for your work. I will certainly check out your fork. But I'm not sure yet about how to proceed with this as this might introduce breaking changes.

On the other hand, themes are usually not updated often, and for new installations a newer Tailwind version does not hurt.

[chrisvidal]

I needed to upgrade to a more recent TW version for a client project anyway.
It is feeling quite necessary for this Mall theme, TW has lots of new interesting stuff.

Yes, it is slightly breaking some of the existing Mall css, but not so much actually.