fix: Import multiple segmentations from coco format json

[Ljung323]

Issue

#246

Changes

• d5287ad pass all segmentation items to create_segmentation function
• 3b76299 fix the content of help

Test

original image with segmentation

before change: only 1 section is imported

after change: all 5 sections are imported

[makseq]

@Ljung323 Could you please update your branch and merge the lastest master branch from the main repo?

[makseq]

@Ljung323 Is it possible to add test for coco import? Something like this: https://github.com/Ljung323/label-studio-sdk/blob/master/tests/custom/converter/test_import_yolo.py

You can merely run the converter on a real simple COCO json, get its output and use it for test assertion. It would be wonderful to have it.

[makseq]

1. Please update to the latest master branch
2. Could you add a test?

[Ljung323]

@makseq
Thank you very much for the review.

I updated the code:

1. Please update to the latest master branch

92f6927

2. Could you add a test?

a3c8ba7 da9abcb