[Feature] Add Mosaic and RandomAffine for yolov5_seg

[JosonChan1998]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

We(me, @yuewangg, @hhaAndroid ) want to support yolov5_seg, this pr supports mosaic and randomaffine for yolov5_seg

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[yue-heu]

There is a problem running browse_dataset.py as follows

Traceback (most recent call last):
  File "tools/analysis_tools/browse_dataset.py", line 262, in <module>
    main()
  File "tools/analysis_tools/browse_dataset.py", line 208, in main
    for i, item in zip(range(display_number), dataset):
  File "/home/*/anaconda3/envs/openmmlab/lib/python3.8/site-packages/mmengine/dataset/base_dataset.py", line 408, in __getitem__
    data = self.prepare_data(idx)
  File "/home/*/workspace/mmyolo/mmyolo/datasets/yolov5_coco.py", line 53, in prepare_data
    return self.pipeline(data_info)
  File "tools/analysis_tools/browse_dataset.py", line 166, in __call__
    data_sample = self.transforms[-1](data)
  File "/home/*/anaconda3/envs/openmmlab/lib/python3.8/site-packages/mmcv/transforms/base.py", line 12, in __call__
    return self.transform(results)
  File "/home/*/workspace/mmdetection/mmdet/datasets/transforms/formatting.py", line 88, in transform
    self.mapping_table[key]] = results[key][valid_idx]
TypeError: only integer scalar arrays can be converted to a scalar index

[JosonChan1998]

There is a problem running browse_dataset.py as follows `` Traceback (most recent call last): File "tools/analysis_tools/browse_dataset.py", line 262, in main() File "tools/analysis_tools/browse_dataset.py", line 208, in main for i, item in zip(range(display_number), dataset): File "/home//anaconda3/envs/openmmlab/lib/python3.8/site-packages/mmengine/dataset/base_dataset.py", line 408, in getitem data = self.prepare_data(idx) File "/home//workspace/mmyolo/mmyolo/datasets/yolov5_coco.py", line 53, in prepare_data return self.pipeline(data_info) File "tools/analysis_tools/browse_dataset.py", line 166, in call data_sample = self.transforms-1 File "/home//anaconda3/envs/openmmlab/lib/python3.8/site-packages/mmcv/transforms/base.py", line 12, in call return self.transform(results) File "/home//workspace/mmdetection/mmdet/datasets/transforms/formatting.py", line 88, in transform self.mapping_table[key]] = results[key][valid_idx] TypeError: only integer scalar arrays can be converted to a scalar index

This is caused by albu augmentation with mask in mmdet, i have make another pr and create a temp albu augmentation in mmyolo. You can try again.

[yue-heu]

LGTM