Support the special single element version of lists

[sorenbs]

GraphQL support single element lists to be written as if they were an object. Ie, these are equivalent:

data: { progress: { create: [{ message }] } }

data: { progress: { create: { message } } }

It would be great if the generated binding could support this as well

[kbrandwijk]

@sorenbs As far as I can see, this only applies to input types, right?