Returns coffee roast type given bean image.

See https://www.kaggle.com/code/dima806/roasted-coffee-bean-image-detection-vit for more details.

```
Classification report:

              precision    recall  f1-score   support

        Dark     1.0000    1.0000    1.0000       160
       Light     1.0000    1.0000    1.0000       160
       Green     1.0000    1.0000    1.0000       160
      Medium     1.0000    1.0000    1.0000       160

    accuracy                         1.0000       640
   macro avg     1.0000    1.0000    1.0000       640
weighted avg     1.0000    1.0000    1.0000       640
```
dark light green medium