updated new flutter version

lib/utils/utils.dart

@@ -525,7 +525,7 @@ class Utils {
             content: Text(message),
             actions: actions == null
                 ? <Widget>[
-                    FlatButton(
+                    TextButton(
                       child: Text(S.of(context).ok),
                       onPressed: onOk == null
                           ? () {
@@ -740,13 +740,13 @@ class Utils {
               title: Text(S.of(context).warning),
               content: Text(S.of(context).are_you_sure_to_empty_basket),
               actions: <Widget>[
-                FlatButton(
+                TextButton(
                   child: Text(S.of(context).cancel),
                   onPressed: () {
                     Navigator.of(context).pop();
                   },
                 ),
-                FlatButton(
+                TextButton(
                   child: Text(S.of(context).yes_i_am_sure),
                   onPressed: () {
                     store.dispatch(new UpdateCartInfo(