Bump django-filter from 2.2 to 2.4.0 (#690)

Bumps [django-filter](https://github.com/carltongibson/django-filter) from 2.2 to 2.4.0.
- [Release notes](https://github.com/carltongibson/django-filter/releases)
- [Changelog](https://github.com/carltongibson/django-filter/blob/master/CHANGES.rst)
- [Commits](https://github.com/carltongibson/django-filter/compare/2.2.0...2.4.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>
Co-authored-by: Pomax <pomax@nihongoresources.com>

requirements.in

@@ -5,7 +5,7 @@ django-cors-headers
 django-debug-toolbar
 django-ajax-selects==1.9.1
 django-environ
-django-filter==2.2
+django-filter==2.4.0
 django-storages
 djangorestframework==3.11.0
 factory_boy

requirements.txt

@@ -16,7 +16,7 @@ django-allauth==0.42.0    # via -r requirements.in
 django-cors-headers==3.4.0  # via -r requirements.in
 django-debug-toolbar==2.2  # via -r requirements.in
 django-environ==0.4.5     # via -r requirements.in
-django-filter==2.2        # via -r requirements.in
+django-filter==2.4.0      # via -r requirements.in
 django-storages==1.9.1    # via -r requirements.in
 django==2.2.13            # via -r requirements.in, django-allauth, django-cors-headers, django-debug-toolbar, django-filter, django-storages, djangorestframework
 djangorestframework==3.11.0  # via -r requirements.in