Add cleanUrls and trailingSlash to vercel.json

vercel.json

@@ -1,6 +1,8 @@
 {
-    "routes": [
+  "cleanUrls": true,
-      { "handle": "filesystem" },
+  "trailingSlash": false,
-      { "src": "/(.*)", "status": 404, "dest": "/404.html" }
+  "routes": [
-    ]
+    { "handle": "filesystem" },
-  }
+    { "src": "/(.*)", "status": 404, "dest": "/404.html" }
+  ]
+}