Update templates/flutter/pubspec.yaml.twig

Co-authored-by: Damodar Lohani <lohanidamodar@users.noreply.github.com>

Author: 2002Bishwajeet

templates/flutter/pubspec.yaml.twig

@@ -18,7 +18,7 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  cookie_jar: ^4.0.2
+  cookie_jar: ^4.0.3
   device_info_plus: ^9.0.2
   flutter_web_auth_2: ^2.1.4
   http: '>=0.13.6 <1.0.1'