Update README_en.md (#5157)

README_en.md

@@ -205,7 +205,7 @@ The relationship between COCO mAP and FPS on Tesla V100 of representative models
 
   - `PP-YOLO v2` is optimized version of `PP-YOLO` which has mAP of 49.5% and 68.9FPS on Tesla V100
 
-  - All these models can be get in [Model Zoo](#ModelZoo)
+  - All these models can be get in [Model Zoo](#model-zoo)
 
 The relationship between COCO mAP and FPS on Qualcomm Snapdragon 865 of representative mobile side models.