hotfix meta

lib/src/javascript_channel.dart

@@ -1,4 +1,4 @@
-import 'package:meta/meta.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';
 
 final RegExp _validChannelNames = RegExp('^[a-zA-Z_][a-zA-Z0-9]*\$');