Bump django from 2.2 to 2.2.8

Bumps [django](https://github.com/django/django) from 2.2 to 2.2.8.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.2...2.2.8)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -1,4 +1,4 @@
 asgiref==3.2.3
-Django==2.2
+Django==2.2.8
 pytz==2019.3
 sqlparse==0.3.0