update changelog and bump version
diff --git a/AUTHORS b/AUTHORS
index 0617765..b132d3f 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -7,3 +7,4 @@
# Organization <fnmatch pattern>
#
Google Inc. <*@google.com>
+Matias Meno <m@tias.me>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 865b0b2..fd3bd74 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+#### 0.12.4
+ * Update to JS version
+ [0.7.23](https://github.com/webcomponents/webcomponentsjs/tree/v0.7.23).
+
#### 0.12.3
* Update to JS version
[0.7.21](https://github.com/webcomponents/webcomponentsjs/tree/v0.7.21).
diff --git a/pubspec.yaml b/pubspec.yaml
index c333213..bf1bdf5 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
name: web_components
-version: 0.12.3
+version: 0.12.4
author: Polymer.dart Authors <web-ui-dev@dartlang.org>
homepage: https://github.com/dart-lang/web-components/
description: >