Declare support for async 2.0.0 (dart-lang/web_socket_channel#9)

pkgs/web_socket_channel/CHANGELOG.md

diff --git a/pkgs/web_socket_channel/CHANGELOG.md b/pkgs/web_socket_channel/CHANGELOG.md
index 40ccf95..f29baf9 100644
--- a/pkgs/web_socket_channel/CHANGELOG.md
+++ b/pkgs/web_socket_channel/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.6
+
+* Declare support for `async` 2.0.0.
+
 ## 1.0.5
 
 * Increase the SDK version constraint to `<2.0.0-dev.infinity`.

pkgs/web_socket_channel/pubspec.yaml

diff --git a/pkgs/web_socket_channel/pubspec.yaml b/pkgs/web_socket_channel/pubspec.yaml
index e9926ec..48f3bce 100644
--- a/pkgs/web_socket_channel/pubspec.yaml
+++ b/pkgs/web_socket_channel/pubspec.yaml
@@ -1,5 +1,5 @@
 name: web_socket_channel
-version: 1.0.6-dev
+version: 1.0.6
 description: StreamChannel wrappers for WebSockets.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/web_socket_channel
@@ -8,7 +8,7 @@
   sdk: '>=1.13.0 <2.0.0'
 
 dependencies:
-  async: '^1.3.0'
+  async: '>=1.3.0 <3.0.0'
   crypto: '>=0.9.2 <3.0.0'
   stream_channel: '^1.2.0'