Support async 2.0.0. (dart-lang/watcher#37)

pkgs/watcher/CHANGELOG.md

diff --git a/pkgs/watcher/CHANGELOG.md b/pkgs/watcher/CHANGELOG.md
index c3acaf5..f07ceaf 100644
--- a/pkgs/watcher/CHANGELOG.md
+++ b/pkgs/watcher/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 0.9.7+4
+
+* Declare support for `async` 2.0.0.
+
 # 0.9.7+3
 
 * Fix a crashing bug on Linux.

pkgs/watcher/pubspec.yaml

diff --git a/pkgs/watcher/pubspec.yaml b/pkgs/watcher/pubspec.yaml
index 90f96f5..15c51c6 100644
--- a/pkgs/watcher/pubspec.yaml
+++ b/pkgs/watcher/pubspec.yaml
@@ -1,5 +1,5 @@
 name: watcher
-version: 0.9.8-dev
+version: 0.9.7+4
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/watcher
 description: >
@@ -8,7 +8,7 @@
 environment:
   sdk: '>=1.9.0 <2.0.0'
 dependencies:
-  async: '^1.10.0'
+  async: '>=1.10.0 <3.0.0'
   path: '>=0.9.0 <2.0.0'
 dev_dependencies:
   benchmark_harness: '^1.0.4'