Bump django from 4.2.17 to 4.2.18 in /backend

Bumps [django](https://github.com/django/django) from 4.2.17 to 4.2.18.
- [Commits](django/django@4.2.17...4.2.18)

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

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

backend/base_requirements.txt

@@ -1,5 +1,5 @@
 cycler==0.11.0
-Django==4.2.17
+Django==4.2.18
 django-cors-headers==3.4.0
 django-csp==3.8
 django-extensions==3.0.3