Bump pytest from 5.0.1 to 5.1.0

Bumps [pytest](https://github.com/pytest-dev/pytest) from 5.0.1 to 5.1.0.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@5.0.1...5.1.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

requirements/test.txt

@@ -2,7 +2,7 @@ mock==2.0.0;python_version=="2.6"  # pyup: ==2.0.0
 mock==3.0.5;python_version>="2.7"
 pytest==3.2.5;python_version=="2.6" or python_version=="3.3"  # pyup: ==3.2.5
 pytest==4.6.3;python_version=="2.7" or python_version=="3.4"
-pytest==5.0.1;python_version>="3.5"
+pytest==5.1.0;python_version>="3.5"
 pytest-travis-fold==1.3.0
 pytest-catchlog==1.2.2;python_version=="2.6"
 pytest-cov==2.5.1;python_version=="2.6"  # pyup: ==2.5.1