update MNN demo link in README (#792)

update MNN demo link in README

README.md

@@ -206,7 +206,7 @@ python tools/eval.py -n  yolox-s -c yolox_s.pth -b 1 -d 1 --conf 0.001 --fp16 --
 * YOLOX with Tengine support: [Tengine](https://github.com/OAID/Tengine/blob/tengine-lite/examples/tm_yolox.cpp) from [BUG1989](https://github.com/BUG1989)
 * YOLOX + ROS2 Foxy: [YOLOX-ROS](https://github.com/Ar-Ray-code/YOLOX-ROS) from [Ar-Ray](https://github.com/Ar-Ray-code)
 * YOLOX Deploy DeepStream: [YOLOX-deepstream](https://github.com/nanmi/YOLOX-deepstream) from [nanmi](https://github.com/nanmi)
-* YOLOX ONNXRuntime C++ Demo: [lite.ai](https://github.com/DefTruth/lite.ai/blob/main/ort/cv/yolox.cpp) from [DefTruth](https://github.com/DefTruth)
+* YOLOX MNN and ONNXRuntime C++ Demo: [YOLOX-MNN](https://github.com/DefTruth/lite.ai.toolkit/blob/main/mnn/cv/mnn_yolox.cpp) and [YOLOX-ONNXRuntime C++](https://github.com/DefTruth/lite.ai.toolkit/blob/main/ort/cv/yolox.cpp) from [DefTruth](https://github.com/DefTruth)
 * Converting darknet or yolov5 datasets to COCO format for YOLOX: [YOLO2COCO](https://github.com/RapidAI/YOLO2COCO) from [Daniel](https://github.com/znsoftm)
 
 ## Cite YOLOX