resolve() function argument was missing in Promise definition (#79)

Author: NiranjanaBinoy

src/JsonRpcEngine.ts

@@ -447,7 +447,7 @@ export class JsonRpcEngine extends SafeEventEmitter {
     handlers: JsonRpcEngineReturnHandler[],
   ): Promise<void> {
     for (const handler of handlers) {
-      await new Promise((resolve, reject) => {
+      await new Promise<void>((resolve, reject) => {
         handler((err) => (err ? reject(err) : resolve()));
       });
     }

src/createAsyncMiddleware.ts

@@ -39,7 +39,7 @@ export function createAsyncMiddleware<T, U>(
     // it is resolved by the return handler passed to the
     // "next" function
     let resolveNextPromise: () => void;
-    const nextPromise = new Promise((resolve) => {
+    const nextPromise = new Promise<void>((resolve) => {
       resolveNextPromise = resolve;
     });