Bump django from 2.2.12 to 2.2.13

Bumps [django](https://github.com/django/django) from 2.2.12 to 2.2.13.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.2.12...2.2.13)

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

requirements.txt

@@ -5,7 +5,7 @@ coverage==4.2
 coveralls==2.0.0
 defusedxml==0.5.0
 dj-database-url==0.4.1
-Django==2.2.12
+Django==2.2.13
 django-allauth==0.41.0
 django-bootstrap-form==3.2.1
 django-daterange-filter==1.3.0