build: update dart constraints

Author: deandreamatias

example/pubspec.yaml

@@ -4,13 +4,13 @@ version: 1.0.0+1
 publish_to: 'none'
 
 environment:
-  sdk: ">=2.19.0 <3.0.0"
+  sdk: '>=3.0.0 <4.0.0'
   flutter: '>=3.10.0'
 
 dependencies:
   flutter:
     sdk: flutter
-  flutter_form_builder: ^9.0.0-dev.1
+  flutter_form_builder: ^9.0.0
   form_builder_file_picker:
       path: ../
 

pubspec.yaml

@@ -8,15 +8,15 @@ funding:
   - https://opencollective.com/flutter-form-builder-ecosystem
 
 environment:
-  sdk: '>=2.19.0 <3.0.0'
+  sdk: '>=3.0.0 <4.0.0'
   flutter: '>=3.10.0'
 
 dependencies:
   community_material_icon: ^5.9.55
   file_picker: ^5.3.0
   flutter:
     sdk: flutter
-  flutter_form_builder: ^9.0.0-dev.1
+  flutter_form_builder: ^9.0.0
 
 platforms:
   android: