Scheduled biweekly dependency update for week 23 (#950)

* Update black from 21.4b2 to 21.5b2
* Update flake8 from 3.9.1 to 3.9.2
* Update sphinx from 3.5.4 to 4.0.2
* Update faker from 8.1.2 to 8.5.1
* Update pytest from 6.2.3 to 6.2.4
* Update pytest-cov from 2.11.1 to 2.12.1
* Update pytest-django from 4.2.0 to 4.4.0

Author: pyup-bot

requirements/requirements-codestyle.txt

@@ -1,4 +1,4 @@
-black==21.4b2
-flake8==3.9.1
+black==21.5b2
+flake8==3.9.2
 flake8-isort==4.0.0
 isort==5.8.0

requirements/requirements-documentation.txt

@@ -1,3 +1,3 @@
 recommonmark==0.7.1
-Sphinx==3.5.4
+Sphinx==4.0.2
 sphinx_rtd_theme==0.5.2

requirements/requirements-testing.txt

@@ -1,8 +1,8 @@
 django-debug-toolbar==3.2.1
 factory-boy==3.2.0
-Faker==8.1.2
-pytest==6.2.3
-pytest-cov==2.11.1
-pytest-django==4.2.0
+Faker==8.5.1
+pytest==6.2.4
+pytest-cov==2.12.1
+pytest-django==4.4.0
 pytest-factoryboy==2.1.0
 snapshottest==0.6.0