fix(README): invalid link of nano model (Megvii-BaseDetection#1475)

fix(README): invalid link of nano model

Author: Yulv-git

README.md

@@ -52,7 +52,7 @@ This repo is an implementation of PyTorch version YOLOX, there is also a [MegEng
 
 |Model |size |mAP<sup>val<br>0.5:0.95 | Params<br>(M) |FLOPs<br>(G)| weights |
 | ------        |:---:  |  :---:       |:---:     |:---:  | :---: |
-|[YOLOX-Nano](./exps/default/nano.py) |416  |25.8  | 0.91 |1.08 | [github](https://github.com/Megvii-BaseDetection/YOLOX/releases/download/0.1.1rc0/yolox_nano.pth) |
+|[YOLOX-Nano](./exps/default/yolox_nano.py) |416  |25.8  | 0.91 |1.08 | [github](https://github.com/Megvii-BaseDetection/YOLOX/releases/download/0.1.1rc0/yolox_nano.pth) |
 |[YOLOX-Tiny](./exps/default/yolox_tiny.py) |416  |32.8 | 5.06 |6.45 | [github](https://github.com/Megvii-BaseDetection/YOLOX/releases/download/0.1.1rc0/yolox_tiny.pth) |
 
 
@@ -61,7 +61,7 @@ This repo is an implementation of PyTorch version YOLOX, there is also a [MegEng
 
 |Model |size |mAP<sup>val<br>0.5:0.95 | Params<br>(M) |FLOPs<br>(G)| weights |
 | ------        |:---:  |  :---:       |:---:     |:---:  | :---: |
-|[YOLOX-Nano](./exps/default/nano.py) |416  |25.3  | 0.91 |1.08 | [github](https://github.com/Megvii-BaseDetection/storage/releases/download/0.0.1/yolox_nano.pth) |
+|[YOLOX-Nano](./exps/default/yolox_nano.py) |416  |25.3  | 0.91 |1.08 | [github](https://github.com/Megvii-BaseDetection/storage/releases/download/0.0.1/yolox_nano.pth) |
 |[YOLOX-Tiny](./exps/default/yolox_tiny.py) |416  |32.8 | 5.06 |6.45 | [github](https://github.com/Megvii-BaseDetection/storage/releases/download/0.0.1/yolox_tiny_32dot8.pth) |
 
 </details>
@@ -246,4 +246,4 @@ It is hoped that every AI practitioner in the world will stick to the concept of
 <div align="center"><img src="assets/sunjian.png" width="200"></div>
 没有孙剑博士的指导，YOLOX也不会问世并开源给社区使用。
 孙剑博士的离去是CV领域的一大损失，我们在此特别添加了这个部分来表达对我们的“船长”孙老师的纪念和哀思。
-希望世界上的每个AI从业者秉持着“持续创新拓展认知边界，非凡科技成就产品价值”的观念，一路向前。
+希望世界上的每个AI从业者秉持着“持续创新拓展认知边界，非凡科技成就产品价值”的观念，一路向前。