weights/README.md

Put the downloaded pre-trained models to this folder.

The directory structure will be arranged as:
```
weights
   |- diffuEraser
      |-brushnet
      |-unet_main
   |- stable-diffusion-v1-5
      |-feature_extractor
      |-...
   |- PCM_Weights
      |-sd15
   |- propainter
      |-ProPainter.pth
      |-raft-things.pth
      |-recurrent_flow_completion.pth
   |- sd-vae-ft-mse
      |-diffusion_pytorch_model.bin
      |-...
   |- README.md
```