Replace flutter.io with flutter.dev (#30562)

diff --git a/packages/flutter_tools/pubspec.yaml b/packages/flutter_tools/pubspec.yaml
index 5086b71..48a0ff7 100644
--- a/packages/flutter_tools/pubspec.yaml
+++ b/packages/flutter_tools/pubspec.yaml
@@ -1,6 +1,6 @@
 name: flutter_tools
 description: Tools for building Flutter applications
-homepage: https://flutter.io
+homepage: https://flutter.dev
 author: Flutter Authors <flutter-dev@googlegroups.com>
 
 environment: