fix client.dynamic._Dispatch.QueryInterface

[junkmd]

THIS IS FOR drop_py2 PLAN! Please see #392.

The client.dynamic._Dispatch.QueryInterface is currently only allowed to be passed a variable argument.

comtypes/comtypes/client/dynamic.py

Lines 85 to 87 in 0fecfea

	def QueryInterface(self, *args):
	"QueryInterface is forwarded to the real com object."
	return self._comobj.QueryInterface(*args)

However, this is a wrapper method for IUnknown.QueryInterface, so I want to change it to a similar argument.

comtypes/comtypes/__init__.py

Line 901 in 0fecfea

def QueryInterface(self, interface, iid=None):

It does not change the name of the named arguments that were existing, so I don't think it will break backward compatibility.

[junkmd]

I will work on this.