chore(deps): bump dj-database-url in /backend in the python group

Bumps the python group in /backend with 1 update: [dj-database-url](https://github.com/jazzband/dj-database-url).


Updates `dj-database-url` from 2.2.0 to 2.3.0
- [Release notes](https://github.com/jazzband/dj-database-url/releases)
- [Changelog](https://github.com/jazzband/dj-database-url/blob/master/CHANGELOG.md)
- [Commits](jazzband/dj-database-url@v2.2.0...v2.3.0)

---
updated-dependencies:
- dependency-name: dj-database-url
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: python
...

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

backend/requirements.txt

@@ -10,7 +10,7 @@ asgiref==3.8.1
     # via django
 beautifulsoup4==4.12.3
     # via -r requirements.in
-dj-database-url==2.2.0
+dj-database-url==2.3.0
     # via -r requirements.in
 django==5.1.2
     # via