django-cors-middleware is depreciated, please use adamchainz/django-cors-headers instead.
It was created at a time when django-cors-headers was not maintained, but it is well maintained now and there is no need to have two different packages for that.
Extract from adamchainz/django-cors-headers README's About section:
django-cors-headers was created in January 2013 by Otto Yiu. It went unmaintained from August 2015 and was forked in January 2016 to the package django-cors-middleware by Laville Augustin at Zeste de Savoir. In September 2016, Adam Johnson, Ed Morley, and others gained maintenance responsibility for django-cors-headers (Issue 110) from Otto Yiu. Basically all of the changes in the forked django-cors-middleware were merged back, or re-implemented in a different way, so it should be possible to switch back. If there's a feature that hasn't been merged, please open an issue about it.