Use common bbox format xywh in DataKey

[twsl]

Changes

Fixes #1471

Type of change

• 🐞 Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Did you update CHANGELOG in case of a major change?

[edgarriba]

@shijianjian

[shijianjian]

@twsl You need to deprecate the previous data key than replace it. Otherwise, it may crash other users' code.

[twsl]

@shijianjian I have no idea how to do that.
And I don't think anyone is using the key name directly because you'd have to use undocumented features rather than fixing the bug.