Add manifestVersion to CloudronManifest

CloudronManifest.json

@@ -1,4 +1,5 @@
 {
+  "manifestVersion": 2,
   "id": "librechat-custom",
   "version": "1.3.1",
   "name": "LibreChat (Co‑op custom)",
@@ -8,4 +9,4 @@
   "volumes": {"data": {"path": "/app/data"}},
   "exposablePorts": {"http": 3080},
   "processes": {"main": "node /app/code/librechat/server/app.js"}
-}
+}