Bump django from 5.1.8 to 5.1.9 in /requirements

Bumps [django](https://github.com/django/django) from 5.1.8 to 5.1.9.
- [Commits](django/django@5.1.8...5.1.9)

---
updated-dependencies:
- dependency-name: django
  dependency-version: 5.1.9
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements/base.txt

@@ -1,4 +1,4 @@
-Django==5.1.8
+Django==5.1.9
 django-environ==0.12.0
 psycopg2==2.9.10
 djangorestframework==3.16.0