Switch import assertions (assert) to import attributes (with)

- tc39/proposal-import-attributes#6 (comment)
- v8/v8@159c82c
- nodejs/node#50140
- https://nodejs.org/en/blog/release/v20.10.0/

index.js

@@ -1105,7 +1105,7 @@ if (
 
 const packageJson = /** @type {Record<string, any>} */ (
   await import(pathToFileURL(`${process.cwd()}/package.json`).href, {
-    assert: { type: 'json' },
+    with: { type: 'json' },
   })
 );