Bump pytest-django from 3.5.1 to 3.8.0 in /requirements (#5988)

Bumps [pytest-django](https://github.com/pytest-dev/pytest-django) from 3.5.1 to 3.8.0.
- [Release notes](https://github.com/pytest-dev/pytest-django/releases)
- [Changelog](https://github.com/pytest-dev/pytest-django/blob/master/docs/changelog.rst)
- [Commits](https://github.com/pytest-dev/pytest-django/compare/v3.5.1...v3.8.0)

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

requirements/dev.txt

@@ -97,9 +97,9 @@ pyflakes==2.1.1 \
     --hash=sha256:17dbeb2e3f4d772725c777fabc446d5634d1038f234e77343108ce445ea69ce0 \
     --hash=sha256:d976835886f8c5b31d47970ed689944a0262b5f3afa00a5a7b4dc81e5449f8a2
 
-pytest-django==3.5.1 \
-    --hash=sha256:4adfe5fb3ed47f0ba55506dd3daf688b1f74d5e69148c10ad2dd2f79f40c0d62 \
-    --hash=sha256:264fb4c506db5d48a6364c311a0b00b7b48a52715bad8839b2d8bee9b99ed6bb
+pytest-django==3.8.0 \
+    --hash=sha256:456fa6854d04ee625d6bbb8b38ca2259e7040a6f93333bfe8bc8159b7e987203 \
+    --hash=sha256:489b904f695f9fb880ce591cf5a4979880afb467763b1f180c07574554bdfd26
 
 # Required by pytest-selenium
 selenium==3.141.0 \