Prepare shelf_web_socket 2.0 for release (#425)

Author: brianquinlan

pkgs/shelf_web_socket/CHANGELOG.md

@@ -1,4 +1,4 @@
-## 2.0.0-wip
+## 2.0.0
 
 * Require Dart `^3.0.0`.
 * **BREAKING:**: Remove support for hijacking WebSocket requests that are not

pkgs/shelf_web_socket/pubspec.yaml

@@ -1,5 +1,5 @@
 name: shelf_web_socket
-version: 2.0.0-wip
+version: 2.0.0
 description: >
   A shelf handler that wires up a listener for every connection.
 repository: https://github.com/dart-lang/shelf/tree/master/pkgs/shelf_web_socket
@@ -14,7 +14,7 @@ environment:
 dependencies:
   shelf: ^1.1.0
   stream_channel: ^2.1.0
-  web_socket_channel: ^2.0.0
+  web_socket_channel: '>=2.0.0 <4.0.0'
 
 dev_dependencies:
   dart_flutter_team_lints: ^2.0.0