Change the appstore id since it is not compat with older version

CloudronManifest.json

@@ -1,5 +1,5 @@
 {
-  "id": "net.syncthing.cloudronapp",
+  "id": "net.syncthing.cloudronapp2",
   "title": "Syncthing",
   "author": "Syncthing Developers",
   "description": "file://DESCRIPTION.md",