fix to add both flutter_test and integration_test (#109650)

packages/integration_test/README.md

@@ -11,7 +11,10 @@ Add a dependency on the `integration_test` and `flutter_test` package in the
 `pubspec.yaml` of the example app:
 
 ```yaml
-integration_test:
+dev_dependencies:
+  integration_test:
+    sdk: flutter
+  flutter_test:
     sdk: flutter
 ```
 
@@ -277,6 +280,7 @@ end
 ```
 
 To build `integration_test/foo_test.dart` from the command line, run:
+
 ```sh
 flutter build ios --config-only integration_test/foo_test.dart
 ```