Get ready to publish 0.21.2. (#61)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd34c51..3a74d31 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
-## 0.21.1+1-dev
+## 0.21.2
 
+* Fix `toObservable(deep: false)` to be shallow again.
 * Remove use of `Maps`, for better compatibility with Dart 2.
 
 ## 0.21.1
diff --git a/pubspec.yaml b/pubspec.yaml
index 8af7b9e..cf97a32 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: observable
-version: 0.21.1+1-dev
+version: 0.21.2
 author: Dart Team <misc@dartlang.org>
 description: Support for marking objects as observable
 homepage: https://github.com/dart-lang/observable