[deps] Update djangorestframework>=3.14,<3.16

Updates the requirements on [djangorestframework](https://github.com/encode/django-rest-framework) to permit the latest version.
- [Release notes](https://github.com/encode/django-rest-framework/releases)
- [Commits](encode/django-rest-framework@3.14.0...3.15.2)

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

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Author: dependabot[bot]

setup.py

@@ -58,7 +58,7 @@
             'docstrfmt~=1.8.0',
         ],
         'rest': [
-            'djangorestframework~=3.14.0',
+            'djangorestframework>=3.14,<3.16',
             'django-filter~=23.2',  # django-filter uses CalVer
             'drf-yasg~=1.21.7',
         ],