fix(overmind-graphql): bring back extending documentnode, where did it go?

Author: christianalfoni

packages/node_modules/overmind-graphql/src/index.ts

@@ -8,8 +8,9 @@ import { print } from 'graphql/language/printer';
 import { Socket as PhoenixSocket } from 'phoenix';
 
 import gqlTag from 'graphql-tag';
+import { DocumentNode } from 'graphql';
 
-export interface Query<Result extends any, Payload extends any = void> {
+export interface Query<Result extends any, Payload extends any = void> extends DocumentNode {
   (payload: Payload): Result;
 }