[fixed] 'componentWillReceiveProps' method name of Position component

just a stub commit for Changelog for react-bootstrap#945

Author: AlexKVal

src/Position.js

@@ -19,6 +19,7 @@ class Position extends React.Component {
     this._needsFlush = true;
   }
 
+  // ToDo: add tests
   componentWillReceiveProps(){
     this._needsFlush = true;
   }