List of unquoted values

[danstewart]

Describe the bug
This is pretty much the reverse of #21 - how do we build an Argument with a list of unquoted values (eg. a list of enums)?

To Reproduce

>>> from graphql_query import Argument
>>> Argument(name="name", value=["value"]).render()
'name: ["value"]'

Expected behavior

'name: [value]'

[danstewart]

One solution is to pass the list as a string instead:

>>> Argument(name="name", value="[one, two, three]").render()
'name: [one, two, three]'