chore(examples): add old api examples

example/src_oldapi/DragHandle/index.tsx

@@ -0,0 +1,21 @@
+import ReactFlow from 'react-flow-renderer';
+
+import DragHandleNode from './DragHandleNode';
+
+const nodeTypes = {
+  dragHandleNode: DragHandleNode,
+};
+
+const elements = [
+  {
+    id: '2',
+    type: 'dragHandleNode',
+    dragHandle: '.custom-drag-handle',
+    style: { border: '1px solid #ddd', padding: '20px 40px' },
+    position: { x: 200, y: 200 },
+  },
+];
+
+const DragHandleFlow = () => <ReactFlow elements={elements} nodeTypes={nodeTypes} />;
+
+export default DragHandleFlow;