Register options mark

[Jarek Zgoda]

With pytest 4.5 using options marker throws PytestUnknownMarkWarning:

PytestUnknownMarkWarning: Unknown pytest.mark.options - is this a typo?
You can register custom marks to avoid this warning - for details, see https://docs.pytest.org/en/latest/mark.html

See https://docs.pytest.org/en/latest/writing_plugins.html#registering-markers