Bump flutter_lints from 3.0.2 to 4.0.0 in /experimental/pedometer/example (#2274)

experimental/pedometer/example/pubspec.yaml

@@ -53,7 +53,7 @@ dev_dependencies:
   # activated in the `analysis_options.yaml` file located at the root of your
   # package. See that file for information about deactivating specific lint
   # rules and activating additional ones.
-  flutter_lints: ^3.0.0
+  flutter_lints: ^4.0.0
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec