Alternative dict form

[pedro-psb]

Hello!
I was looking in pytest issues for something related to more readable form of declaring @pytest.mark.parametrize, because I wanted to propose the one I wished to use.

I would issue it there, but I think it would be more appropriate to do it here. I've implemented I similiar solution, but with sligtly different form, and I think it could be merged into this plugin like so:

@pytest.mark.suite({
    "argnames": ("arg1", "arg2"),
    "test-a": ("a", "b"),
    "test-b": ("foo", "bar"),
})

This new form could be an override of the @pytest.mark.suite, so when the first arg is a dict it uses my form, otherwhise ir uses your default **kwargs form. What do you think?