Export unregister as default in serviceWorker.js

Changed the export of the unregister function to a default export to standardize import usage and improve module interoperability.

Author: JorchCortez

src/serviceWorker.js

@@ -12,7 +12,7 @@
 
 
 
-export function unregister() {
+export default function unregister() {
   if ('serviceWorker' in navigator) {
     navigator.serviceWorker.ready
       .then(registration => {