refactor(dart_frog_gen): update to Dart 3 and Very Good Analysis 5 (#681)

Author: renancaraujo

packages/dart_frog_gen/analysis_options.yaml

@@ -1 +1 @@
-include: package:very_good_analysis/analysis_options.4.0.0.yaml
+include: package:very_good_analysis/analysis_options.5.0.0.yaml

packages/dart_frog_gen/pubspec.yaml

@@ -7,7 +7,7 @@ issue_tracker: https://github.com/VeryGoodOpenSource/dart_frog/issues
 documentation: https://dartfrog.vgv.dev/docs/overview
 
 environment:
-  sdk: ">=2.19.0 <3.0.0"
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   path: ^1.8.1
@@ -16,4 +16,4 @@ dependencies:
 dev_dependencies:
   mocktail: ^0.3.0
   test: ^1.19.2
-  very_good_analysis: ^4.0.0
+  very_good_analysis: ^5.0.0