Merge pull request #27 from grundid/master

fix issue with not using decoration from state and not showing validation error

Author: danvick

lib/src/form_builder_file_picker.dart

@@ -105,7 +105,7 @@ class FormBuilderFilePicker extends FormBuilderField<List<PlatformFile>> {
             final state = field as _FormBuilderFilePickerState;
 
             return InputDecorator(
-              decoration: decoration,
+              decoration: state.decoration,
               child: Column(
                 children: <Widget>[
                   Row(