Loosened version restriction on pytest (#1)
Loosened version restriction on pytest (#1)

Pinning pytest version to 3.1.0 caused this error:

_pytest.vendored_packages.pluggy.PluginValidationError: Plugin
'purkinje' could not be loaded: (pytest 3.2.3
(/Users/hanxue/.virtualenvs/quest-backend/lib/python3.6/site-packages),
Requirement.parse('pytest==3.1.0'))!

bbiskup/pytest-purkinje,bbiskup/pytest-purkinje