pub updates

pkgs/markdown/pubspec.yaml

diff --git a/pkgs/markdown/pubspec.yaml b/pkgs/markdown/pubspec.yaml
index 331513f..cb5bc77 100644
--- a/pkgs/markdown/pubspec.yaml
+++ b/pkgs/markdown/pubspec.yaml
@@ -1,7 +1,9 @@
 name: markdown
-version: 0.5.0
+version: 0.5.1-dev
 author: Dart Team <misc@dartlang.org>
 description: A library for converting markdown to HTML.
 homepage: https://github.com/dpeek/dart-markdown
+environment:
+  sdk: '>=1.0.0 <2.0.0'
 dev_dependencies:
-  unittest: any
+  unittest: '>=0.9.0 <0.11.0'