Make tests run on the bots.

The version number was such that no compatible version of `test` could
be found.

Review URL: .
diff --git a/pubspec.yaml b/pubspec.yaml
index 1b3fb5c..e5b13cc 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,8 @@
 name: matcher
-version: 0.12.1-dev
+# This version should really be 0.12.1-dev, but test depends on matcher <0.12.1,
+# so we're using + instead.
+version: 0.12.0+dev
 author: Dart Team <>
 description: Support for specifying test expectations