Bump pytest from 3.7.4 to 3.8.0 (#202)

Bumps [pytest](https://github.com/pytest-dev/pytest) from 3.7.4 to 3.8.0.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@3.7.4...3.8.0)

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

Pipfile

@@ -16,6 +16,6 @@ coveralls = "==1.5.0"
 flake8 = "==3.5.0"
 flake8-docstrings = "==1.3.0"
 flake8-isort = "==2.5"
-pytest = "==3.7.4"
+pytest = "==3.8.0"
 pytest-cov = "==2.6.0"
 pytest-selenium = "==1.14.0"