upgrade unittest dependency
diff --git a/pubspec.yaml b/pubspec.yaml
index dbffdce..87d6fc7 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -11,4 +11,4 @@
   utf: '>=0.9.0 <0.10.0'
 dev_dependencies:
   path: '>=0.9.0 <2.0.0'
-  unittest: '>=0.10.0 <0.11.0'
+  unittest: '>=0.10.0 <0.12.0'