Fix type for extensions option

Author: danielrearden

src/index.js

@@ -125,7 +125,9 @@ export type OptionsData = {|
    *
    * This function may be async.
    */
-  extensions?: (info: RequestInfo) => { [key: string]: mixed, ... },
+  extensions?: (
+    info: RequestInfo,
+  ) => { [key: string]: mixed, ... } | Promise<{ [key: string]: mixed, ... }>,
 
   /**
    * A boolean to optionally enable GraphiQL mode.

types/index.d.ts

@@ -120,7 +120,9 @@ export interface OptionsData {
    *
    * This function may be async.
    */
-  extensions?: (info: RequestInfo) => { [key: string]: unknown };
+  extensions?: (
+    info: RequestInfo,
+  ) => { [key: string]: unknown } | Promise<{ [key: string]: unknown }>;
 
   /**
    * A boolean to optionally enable GraphiQL mode.