ServiceWorker: Update version

public/service-worker.js

 
 let OFFLINE_URL = "/offline.html"; // Match your offline page URL
-let PRE_CACHE = "pre-cache-v1"; // Manually update version or generate one server-site
+let PRE_CACHE = "pre-cache-v2"; // Manually update version or generate one server-site
 let PRE_CACHE_URL = "/pre-cache.json" // Match your pre-cache URL
 let RUNTIME_CACHE = "runtime-cache";