Support graphql-config

[legopin]

Graphql-config is a growing config specification that seeks to simplify tools that need to have settings about graphql, it would be nice if this tool can also use the existing configuration options in a .graphqlconfig file.

https://github.com/prisma/graphql-config/blob/master/specification.md

{
  "schemaPath": "./schema.graphql"
}

Link to graphql-config repo

[spyl94]

Sure, I see how we can do this. The only things we need is the base branch but master should handle most of the cases. Will do a PR for this 👍