fix: maintenance update

- updated maintenance schedule
- updated router example app
- removed broken banner
- added platforms entry to pubspec

pubspec.yaml

@@ -22,7 +22,6 @@ dependencies:
   collection: ^1.15.0
   # Remove the path and use pub one after publish the stacked_shared
   stacked_shared: ^1.3.1
-  #universal_io
   universal_io: ^2.0.4
   path: ^1.8.2