chore(deps): update dependency dart to v3

Author: renovate[bot]

pubspec.yaml

@@ -6,7 +6,7 @@ repository: https://github.com/Stacked-Org/gql.git
 issue_tracker: https://github.com/Stacked-Org/framework/issues
 
 environment:
-  sdk: '>=2.13.0 <3.0.0'
+  sdk: '3.12.1'
   flutter: '>=1.17.0'
 
 dependencies: