Bump django-configurations from 2.0 to 2.1

Bumps [django-configurations](https://github.com/jazzband/django-configurations) from 2.0 to 2.1.
- [Release notes](https://github.com/jazzband/django-configurations/releases)
- [Commits](jazzband/django-configurations@2.0...2.1)

Signed-off-by: dependabot[bot] <support@dependabot.com>

requirements.txt

@@ -1,6 +1,6 @@
 asgi-redis==1.4.3
 Django==1.11.26
-django-configurations==2.0
+django-configurations==2.1
 easy-thumbnails==2.5
 django-autocomplete-light==3.2.10
 django-ckeditor==5.3.1