removed unneeded async/await

lib/fetch/bg/fetch.js

@@ -26,10 +26,10 @@
 
 	let requestId = 1;
 
-	browser.runtime.onMessage.addListener(async request => {
+	browser.runtime.onMessage.addListener(request => {
 		if (request.method) {
 			try {
-				return await onRequest(request);
+				return onRequest(request);
 			} catch (error) {
 				return { error: error.toString() };
 			}