fix: allow iframe to work in stricter cross-origin policy

close nuxt/learn.nuxt.com#68

Co-authored-by: sqcheah <sqcheah@users.noreply.github.com>

Author: antfu

packages/devtools/src/runtime/plugins/view/client.ts

@@ -129,6 +129,8 @@ export async function setupDevToolsClient({
       try {
         iframe = document.createElement('iframe')
         iframe.id = 'nuxt-devtools-iframe'
+        iframe.allow = 'cross-origin-isolated'
+        iframe.setAttribute('credentialless', 'true')
         iframe.src = initialUrl
         iframe.onload = async () => {
           try {