Update django-cors-headers requirement from <2.5,>=2.4 to >=2.4,<3.6

Updates the requirements on [django-cors-headers](https://github.com/adamchainz/django-cors-headers) to permit the latest version.
- [Release notes](https://github.com/adamchainz/django-cors-headers/releases)
- [Changelog](https://github.com/adamchainz/django-cors-headers/blob/master/HISTORY.rst)
- [Commits](adamchainz/django-cors-headers@2.4.0...3.5.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements.txt

@@ -1,7 +1,7 @@
 django>=2.2.10,<2.3
 django-extensions>=2.1,<2.2
 django-filter>=2.0,<2.1
-django-cors-headers>=2.4,<2.5
+django-cors-headers>=2.4,<3.6
 whitenoise>=3.3,<4.0
 psycopg2==2.8.4
 gunicorn==20.0.4