depend on quiver explicitly (#4)

diff --git a/packages/flutter_image/pubspec.yaml b/packages/flutter_image/pubspec.yaml
index 5ebaf5e..1fd0cab 100644
--- a/packages/flutter_image/pubspec.yaml
+++ b/packages/flutter_image/pubspec.yaml
@@ -15,4 +15,5 @@
     sdk: flutter
 
 dev_dependencies:
+  quiver: '>=0.24.0 <2.0.0'
   test: any