Update React and unfetch

- Get rid of message about Next 11

Author: giraffesyo

examples/with-zeit-fetch/package.json

@@ -10,9 +10,9 @@
     "@vercel/fetch": "6.1.0",
     "next": "latest",
     "node-fetch": "2.6.1",
-    "react": "^16.8.4",
-    "react-dom": "^16.8.4",
-    "unfetch": "4.1.0"
+    "react": "17.0.1",
+    "react-dom": "17.0.1",
+    "unfetch": "4.2.0"
   },
   "license": "MIT"
 }