Update README.md (#4510)

configs/cityscapes/README.md

@@ -17,7 +17,7 @@
 - All models were trained on `cityscapes_train`, and tested on `cityscapes_val`.
 - 1x training schedule indicates 64 epochs which corresponds to slightly less than the 24k iterations reported in the original schedule from the [Mask R-CNN paper](https://arxiv.org/abs/1703.06870)
 - COCO pre-trained weights are used to initialize.
-- A conversion [script](../../tools/convert_datasets/cityscapes.py) is provided to convert Cityscapes into COCO format. Please refer to [install.md](../../docs/install.md#prepare-datasets) for details.
+- A conversion [script](../../tools/convert_datasets/cityscapes.py) is provided to convert Cityscapes into COCO format. Please refer to [install.md](../../docs/1_exist_data_model.md#prepare-datasets) for details.
 - `CityscapesDataset` implemented three evaluation methods. `bbox` and `segm` are standard COCO bbox/mask AP. `cityscapes` is the cityscapes dataset official evaluation, which may be slightly higher than COCO.
 
 ### Faster R-CNN