Bump django-cors-headers from 4.3.0 to 4.3.1 in /backend

Bumps [django-cors-headers](https://github.com/adamchainz/django-cors-headers) from 4.3.0 to 4.3.1.
- [Changelog](https://github.com/adamchainz/django-cors-headers/blob/main/CHANGELOG.rst)
- [Commits](adamchainz/django-cors-headers@4.3.0...4.3.1)

---
updated-dependencies:
- dependency-name: django-cors-headers
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

backend/requirements.txt

@@ -3,7 +3,7 @@ autopep8==2.0.4
 certifi==2023.7.22
 charset-normalizer==3.3.2
 Django==4.2.7
-django-cors-headers==4.3.0
+django-cors-headers==4.3.1
 django-rest-passwordreset==1.3.0
 djangorestframework==3.14.0
 idna==3.4