[TypeScript] Add serviceWorker typescript definition

Author: brunolemos

Diff for: packages/react-scripts/template/src/serviceWorker.d.ts

@@ -0,0 +1,8 @@
+export type Config = {
+  onSuccess?: (registration: ServiceWorkerRegistration) => void
+  onUpdate?: (registration: ServiceWorkerRegistration) => void
+}
+
+export function register(config: Config): void
+
+export function unregister(): void