[feature request] Update format for compatibility with Deepstack

[robmarkcole]

Using the current data set with https://github.com/johnolafenwa/deepstack-trainer results in error No labels found in /content/fire-dataset/train/labels.cache. Can not train without labels I believe due to the dataset being in Pascal VOC format. Deepstack requires yolo formatted data: https://docs.deepstack.cc/custom-models/datasetprep/index.html#change-annotation-to-yolo-format
I uses Roboflow to convert the dataset to yolo format and trained the deepstack model but in production on deepstacl it does not perform well, and I assume there is a data formatting issue: https://github.com/robmarkcole/fire-detection-from-images/blob/master/pytorch/object-detection/yolov5/deepstack/deepstack_custom_training_fire.ipynb

Scope of this request is to update the format, or alternatively provide a second download link in yolo format