Django-hmin

Suddenly mwhawkins found out (https://github.com/xfenix/django-hmin/issues/3) critical bug: hmin 0.5.2 strip spaces BEFORE tags, so scenarios like "some text &lt;a href="">...</a>" leads to "some text&lt;a href="">...</a>". This is incorrect behaviour.
Also, because of this fix, we got 2x time speedup (because i replaced complicated regexp with string replace and very simple regexp).

Huge update! 🚀
* Rewritten to 3.7+ python with full typing support.
* Main repo now supports installation via flit. But if you want to use plain old pip, download django-hmin-0.5.1.tar.gz archive.
* 100% test coverage support
* heavy tests coverage!
* integration test (very simple, but it here)
* tests for various environments (python 3.7/3.8, django 2/3)
* tested is package installable
* full support plenty of PEP's (typing, docstring)
* `python -m` CLI support
* last, but not least — complete CI/CD via github actions!