Log Message:
py-django-filter: updated to 2.4.0

Version 2.4.0 (2020-9-27)
--------------------------
* SECURITY: Added a ``MaxValueValidator`` to the form field for
  ``NumberFilter``. This prevents a potential DoS attack if numbers with very
  large exponents were subsequently converted to integers.

  The default limit value for the validator is ``1e50``.

  The new ``NumberFilter.get_max_validator()`` allows customising the used
  validator, and may return ``None`` to disable the validation entirely.

* Added testing against Django 3.1 and Python 3.9.

  In addition tests against Django main development branch are now required to
  pass.

Version 2.3.0 (2020-6-5)
------------------------
* Fixed import of FieldDoesNotExist.
* Added testing against Django 3.0.
* Declared support for, and added testing against, Python 3.8.
* Fix filterset multiple inheritance bug
* Allowed customising default lookup expression.
* Drop Django 2.1 and below
* Fixed IsoDateTimeRangeFieldTests for Django 3.1
* Require tests to pass against Django `master`.