Update version numbers in pubspec.yaml.
diff --git a/pubspec.yaml b/pubspec.yaml
index 71d304a..2fa26c2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -6,10 +6,10 @@
   and as such, require the use of the WebDriver remote server.
 homepage: https://github.com/google/webdriver.dart
 environment:
-  sdk: '>=1.9.0-dev.4.0 <2.0.0'
+  sdk: '>=1.9.0-dev.5.0 <2.0.0'
 dependencies:
   crypto: '^0.9.0'
   matcher: '^0.11.4'
 dev_dependencies:
   path: '^1.3.2'
-  unittest: '^0.11.5'
+  unittest: '^0.11.5+2'