Update README.md

Author: leiqing1

examples/vision/segmentation/paddleseg/cpp/README.md

@@ -88,4 +88,4 @@ PaddleSegModel模型加载和初始化，其中model_file为导出的Paddle模
 - [模型介绍](../../)
 - [Python部署](../python)
 - [视觉模型预测结果](../../../../../docs/api/vision_results/)
-- [如何切换模型推理后端引擎](../../../../how_to_change_backend.md)
+- [如何切换模型推理后端引擎](../../../../../docs/runtime/how_to_change_backend.md)