Bump pytest from 5.3.0 to 5.3.1

Bumps [pytest](https://github.com/pytest-dev/pytest) from 5.3.0 to 5.3.1.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/5.3.1/CHANGELOG.rst)
- [Commits](https://github.com/pytest-dev/pytest/compare/5.3.0...5.3.1)

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

requirements-dev.txt

@@ -8,7 +8,7 @@ flake8==3.7.9
 flake8-type-annotations==0.1.0
 flake8-tidy-imports==3.1.0
 mypy==0.740
-pytest==5.3.0
+pytest==5.3.1
 pytest-asyncio==0.10.0
 pytest-cov==2.8.1
 pytest-mock==1.12.1