Update reference onto GraphQL.Client to a more recent version

[reureu]

Hi guys,

This issue is tightly related to #28

GraphQL.Client.Extensions currently depends on GraphQL.Client 1.x, which in turn depends on GraphQL.Common.
GraphQL.Common is legacy and no longer maintained.

With GraphQL.Client 2.x, this dependency on GraphQL.Common was removed.

I think it would be a good idea to update GraphQL.Client.Extensions to a more recent release of GraphQL.Client, so that it no longer relies on obsolete libraries. It would probably make the maintenance of this library easier in the future.

And while you are working on updating the dependencies, you released a new version of GraphQL.Query.Builder yesterday.
Would you consider updating this dependency too?

Kind regards,
Reureu