Require latest flutter 1.9.1

fixes #200

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## 0.9.8+1
+  * Require latest flutter stable version
+
 ## 0.9.8
 
   * Hero Widget is no longer used (thanks @localpcguy)

pubspec.yaml

@@ -1,6 +1,6 @@
 name: chewie
 description: A video player for Flutter with Cupertino and Material play controls
-version: 0.9.8
+version: 0.9.8+1
 homepage: https://github.com/brianegan/chewie
 authors:
   - Brian Egan <brian@brianegan.com>
@@ -8,6 +8,7 @@ authors:
 
 environment:
   sdk: ">=2.0.0-dev.28.0 <3.0.0"
+  flutter: ">=1.9.1 <2.0.0"
 
 dependencies:
   open_iconic_flutter: ">=0.3.0 <0.4.0"