remove warning that data need be an object [data allow object and array] (#82)

* Update SortableList.js

* Update data accept PropTypes

Author: eriveltonelias

src/SortableList.js

@@ -15,7 +15,7 @@ uniqueRowKey.id = 0
 
 export default class SortableList extends Component {
   static propTypes = {
-    data: PropTypes.object.isRequired,
+    data: PropTypes.oneOfType([PropTypes.array, PropTypes.object]).isRequired, 
     order: PropTypes.arrayOf(PropTypes.any),
     style: ViewPropTypes.style,
     contentContainerStyle: ViewPropTypes.style,