Bump django from 1.6 to 2.2.24 in /requirements

Bumps [django](https://github.com/django/django) from 1.6 to 2.2.24.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@1.6...2.2.24)

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

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

requirements/package.txt

@@ -1,2 +1,2 @@
-Django==1.6
+Django==2.2.24
 gdata==2.0.18