Widen the Dart SDK constraint to include 1.13.0.

Closes #322

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1302023002 .
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e6ac7ec..cf23733 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.12.4+4
+
+* Widen the Dart SDK constraint to include `1.13.0`.
+
 ## 0.12.4+3
 
 * Make source maps work properly in the browser when not using `--pub-serve`.
diff --git a/pubspec.yaml b/pubspec.yaml
index 1705ab8..3f7cfb2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,10 +1,10 @@
 name: test
-version: 0.12.4+3
+version: 0.12.4+4
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test
 environment:
-  sdk: '>=1.11.0 <1.13.0'
+  sdk: '>=1.11.0 <1.14.0'
 dependencies:
   analyzer: '>=0.23.0 <0.27.0'
   args: '>=0.12.1 <0.14.0'