Bump djangorestframework from 3.7.4 to 3.9.3

[dependabot-preview]

Bumps djangorestframework from 3.7.4 to 3.9.3.

Release notes

Sourced from djangorestframework's releases.

Version 3.9.3

This is the last Django REST Framework release that will support Python 2.
Be sure to upgrade to Python 3 before upgrading to Django REST Framework 3.10.

• Adjusted the compat check for django-guardian to allow the last guardian
  version (v1.4.9) compatible with Python 2. #6613

Version 3.9.2

See Release Notes for details.

Version 3.9.1

Change Notes:
https://www.django-rest-framework.org/community/release-notes/#39x-series

Verision 3.9.0

Release announcement:
https://www.django-rest-framework.org/community/3.9-announcement/

Change Notes:
https://www.django-rest-framework.org/community/release-notes/#39x-series

Version 3.8.2

Point release for 3.8.x series

• Fix read_only + default unique_together validation. #5922
• authtoken.views import coreapi from rest_framework.compat, not directly. #5921
• Docs: Add missing argument 'detail' to Route #5920

Version 3.8.1

• Use old url_name behavior in route decorators #5915

  For list_route and detail_route maintain the old behavior of url_name,
  basing it on the url_path instead of the function name.

Version 3.8

• Release Announcement

• 3.8.0 Milestone

• Breaking Change: Alter read_only plus default behaviour. #5886

  read_only fields will now always be excluded from writable fields.

  Previously read_only fields with a default value would use the default for create and update operations.

  In order to maintain the old behaviour you may need to pass the value of read_only fields when calling save() in
  the view:

    def perform_create(self, serializer):
        serializer.save(owner=self.request.user)
  

... (truncated)

Commits

• 7f16ed7 Correct version number in release notes.
• 83d09c7 Update version and release notes for v3.9.3.
• bf9859d Adjust django-guardian check for PY2 compatible version. (#6613)
• 59a5a5a Merge pull request #6611 from dsanders11/patch-1
• 95e28b2 Fix typo in docs
• 1ac0f63 Fix private attributes ignore in documentation (#6601)
• db65282 Merge pull request #6588 from rawteech/master
• f8c4e50 Minor documentation fixes (#6581)
• 29cbe57 Fix DeprecationWarning in tests (#6551)
• cceb416 Link DRF Condition (cache headers) third party package. (#6557)
• Additional commits viewable in compare view

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[dependabot-preview]

Superseded by #1723.