openapi-fetch: provide type for Request option in client methods

Author: sgrishchenko

packages/openapi-fetch/src/index.d.ts

@@ -119,6 +119,7 @@ export type RequestOptions<T> = ParamsOption<T> &
     bodySerializer?: BodySerializer<T>;
     parseAs?: ParseAs;
     fetch?: ClientOptions["fetch"];
+    Request?: ClientOptions["Request"];
     headers?: HeadersOptions;
   };