Scheduled biweekly dependency update for week 05 (django-json-api#765)

* Update django-debug-toolbar from 2.1 to 2.2
* Update faker from 3.0.0 to 4.0.0
* Update pytest from 5.3.1 to 5.3.5
* Update pytest-django from 3.7.0 to 3.8.0

Author: pyup-bot

requirements/requirements-testing.txt

@@ -1,7 +1,7 @@
-django-debug-toolbar==2.1
+django-debug-toolbar==2.2
 factory-boy==2.12.0
-Faker==3.0.0
-pytest==5.3.1
+Faker==4.0.0
+pytest==5.3.5
 pytest-cov==2.8.1
-pytest-django==3.7.0
+pytest-django==3.8.0
 pytest-factoryboy==2.0.3