Bump django from 1.8.18 to 2.2.24

Bumps [django](https://github.com/django/django) from 1.8.18 to 2.2.24.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@1.8.18...2.2.24)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
...

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

requirements.txt

@@ -14,7 +14,7 @@ cryptography==2.0.3
 cycler==0.10.0
 descartes==1.1.0
 dj-database-url==0.4.2
-Django==1.8.18
+Django==2.2.24
 django-appconf==1.0.2
 django-classy-tags==0.8.0
 django-cms==3.4.4