Bump pytest from 5.2.3 to 5.2.4

Bumps [pytest](https://github.com/pytest-dev/pytest) from 5.2.3 to 5.2.4.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@5.2.3...5.2.4)

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

requirements-dev.txt

@@ -1,5 +1,5 @@
 wheel==0.33.6
-pytest==5.2.3
+pytest==5.2.4
 pytest-cov
 flake8==3.7.9
 autopep8==1.4.4