Update pubspec.yaml

remove -dev
diff --git a/pubspec.yaml b/pubspec.yaml
index 35a9ba4..933b469 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: html
-version: 0.12.1-dev
+version: 0.12.1
 author: Dart Team <misc@dartlang.org>
 description: A library for working with HTML documents.
 homepage: https://github.com/dart-lang/html5lib