Bump djangorestframework from 3.13.1 to 3.15.2

Bumps [djangorestframework](https://github.com/encode/django-rest-framework) from 3.13.1 to 3.15.2.
- [Release notes](https://github.com/encode/django-rest-framework/releases)
- [Commits](encode/django-rest-framework@3.13.1...3.15.2)

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

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

requirements.txt

@@ -2,7 +2,7 @@ beautifulsoup4
 Django~=3.2.16
 django-admin-autocomplete-list-filter==1.0.1
 django-guardian==2.4.0
-djangorestframework==3.13.1
+djangorestframework==3.15.2
 drf-nested-routers==0.93.4
 humanfriendly
 jsonfield==3.1.0