Fix mypy==0.700 compatibility.

[singulared]

mypy.api.run method should take List[str] of args.
https://docs.python.org/3/library/argparse.html#argparse.ArgumentParser.parse_args
https://github.com/python/mypy/blob/d40990f5b91b1f06918222d1041441b7ff63f79a/mypy/api.py#L71

[tomv564]

Thanks! Unsure how this stopped working in 0.700?

[singulared]

I didn't investigate this but running pyls with python 3.7.3 and mypy 0.700 produce list object expected error on initialization.
With mypy==0.670 initialization pass correctly.

[tomv564]

Now released in 1.6.0