Add vercel.json for default React vite.js template (#755)

Fixes #741 
See: https://vercel.com/docs/project-configuration#rewrites-examples

scaffold/vercel.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "https://openapi.vercel.sh/vercel.json",
+  "rewrites": [
+    {
+      "source": "/(.*)",
+      "destination": "/index.html"
+    }
+  ]
+}