update stream_transform example to package:web

Fixes a deprecation warning from the latest SDK.
diff --git a/.github/workflows/stream_transform.yaml b/.github/workflows/stream_transform.yaml
index a36a776..38be5cc 100644
--- a/.github/workflows/stream_transform.yaml
+++ b/.github/workflows/stream_transform.yaml
@@ -59,7 +59,7 @@
         # Add macos-latest and/or windows-latest if relevant for this package.
         os: [ubuntu-latest]
         # Bump SDK for Legacy tests when changing min SDK.
-        sdk: [3.1, dev]
+        sdk: [3.4, dev]
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: dart-lang/setup-dart@e630b99d28a3b71860378cafdc2a067c71107f94
diff --git a/pkgs/stream_transform/CHANGELOG.md b/pkgs/stream_transform/CHANGELOG.md
index 5c6a78d..b09778b 100644
--- a/pkgs/stream_transform/CHANGELOG.md
+++ b/pkgs/stream_transform/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## 2.1.2-wip
 
+- Require Dart 3.4 or greater.
+
 ## 2.1.1
 
 - Require Dart 3.1 or greater
diff --git a/pkgs/stream_transform/example/main.dart b/pkgs/stream_transform/example/main.dart
index 70b3e7f..8224393 100644
--- a/pkgs/stream_transform/example/main.dart
+++ b/pkgs/stream_transform/example/main.dart
@@ -2,13 +2,12 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:html';
-
 import 'package:stream_transform/stream_transform.dart';
+import 'package:web/web.dart';
 
 void main() {
-  var firstInput = document.querySelector('#first_input') as InputElement;
-  var secondInput = document.querySelector('#second_input') as InputElement;
+  var firstInput = document.querySelector('#first_input') as HTMLInputElement;
+  var secondInput = document.querySelector('#second_input') as HTMLInputElement;
   var output = document.querySelector('#output')!;
 
   _inputValues(firstInput)
@@ -21,6 +20,6 @@
   });
 }
 
-Stream<String?> _inputValues(InputElement element) => element.onKeyUp
+Stream<String?> _inputValues(HTMLInputElement element) => element.onKeyUp
     .debounce(const Duration(milliseconds: 100))
     .map((_) => element.value);
diff --git a/pkgs/stream_transform/pubspec.yaml b/pkgs/stream_transform/pubspec.yaml
index f17bad3..91840b7 100644
--- a/pkgs/stream_transform/pubspec.yaml
+++ b/pkgs/stream_transform/pubspec.yaml
@@ -4,10 +4,11 @@
 repository: https://github.com/dart-lang/tools/tree/main/pkgs/stream_transform
 
 environment:
-  sdk: ^3.1.0
+  sdk: ^3.4.0
 
 dev_dependencies:
   async: ^2.5.0
   dart_flutter_team_lints: ^3.0.0
   fake_async: ^1.3.0
   test: ^1.16.0
+  web: ^1.1.0