build: override vercel build and change the output dir

vercel.json

@@ -1,14 +1,5 @@
 {
   "cleanUrls": true,
-  "version": 2,
-  "builds": [
-    {
-      "src": "package.json",
-      "use": "@vercel/static-build",
-      "config": {
-        "distDir": "build"
-      }
-    }
-  ],
-  "outputDirectory": ".vercel/output"
+  "outputDirectory": "build",
+  "buildCommand": "echo ✅  Skipping build to use existing built files"
 }