Updates version (#57)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7a10387..8662956 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,16 @@
-## 0.13.7
+## 0.14.0
+
+### New features
 
 * Supports nested at-rules.
 * Supports nested HTML comments in CSS comments and vice-versa.
 
+### Breaking changes
+
+* The `List<RuleSet> rulesets` field on `MediaDirective`, `HostDirective`, and
+  `StyletDirective` has been replaced by `List<TreeNode> rules` to allow nested
+  at-rules in addition to rulesets.
+
 ## 0.13.6
 
 * Adds support for `@viewport`.
diff --git a/pubspec.yaml b/pubspec.yaml
index 8634c95..2111ec9 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: csslib
-version: 0.13.7
+version: 0.14.0
 author: Dart Team <misc@dartlang.org>
 description: A library for parsing CSS.
 homepage: https://github.com/dart-lang/csslib