Update djangorestframework from 3.14.0 to 3.15.0

Author: pyup-bot

Diff for: {{cookiecutter.project_slug}}/requirements/base.txt

@@ -40,7 +40,7 @@ django-compressor==4.4  # https://github.com/django-compressor/django-compressor
 django-redis==5.4.0  # https://github.com/jazzband/django-redis
 {%- if cookiecutter.use_drf == 'y' %}
 # Django REST Framework
-djangorestframework==3.14.0  # https://github.com/encode/django-rest-framework
+djangorestframework==3.15.0  # https://github.com/encode/django-rest-framework
 django-cors-headers==4.3.1  # https://github.com/adamchainz/django-cors-headers
 # DRF-spectacular for api documentation
 drf-spectacular==0.27.1  # https://github.com/tfranzel/drf-spectacular