目标检测模型离线量化示例

[lizexu123]

修改为Paddle2.6和Paddleslim2.6的组合，并添加了yolov3_r50vd_dcn_270e_coco示例

[paddle-bot]

Thanks for your contribution!

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 3 committers have signed the CLA.

✅ lizexu123
❌ RachelXu7
❌ ceci3
_{You have signed the CLA already but the status is still pending? Let us recheck it.}