Merge pull request #61 from kevmoo/tweak_pubspec

updated Dart sdk version
diff --git a/pubspec.yaml b/pubspec.yaml
index 3c7e064..60c5e67 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -6,7 +6,7 @@
   and as such, require the use of the WebDriver remote server.
 homepage: https://github.com/google/webdriver.dart
 environment:
-  sdk: '>=1.9.0-dev.10.4 <2.0.0'
+  sdk: '>=1.9.0 <2.0.0'
 dependencies:
   crypto: '^0.9.0'
   matcher: '^0.11.4+3'