Bump pytest from 3.6.1 to 3.8.0 in /{{cookiecutter.app_name}}

Bumps [pytest](https://github.com/pytest-dev/pytest) from 3.6.1 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](https://github.com/pytest-dev/pytest/compare/3.6.1...3.8.0)

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

{{cookiecutter.app_name}}/Pipfile

@@ -45,7 +45,7 @@ environs = "==4.0.0"
 
 [dev-packages]
 # Testing
-pytest = "==3.6.1"
+pytest = "==3.8.0"
 WebTest = "==2.0.30"
 factory-boy = "==2.11.*"