Add quantized concat conversion (#30887)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30887
Support to convert quantized concat from pytorch to caffe2
Test Plan:
python test/onnx/test_pytorch_onnx_caffe2_quantized.py TestQuantizedOps.test_cat
Imported from OSS
Differential Revision: D18855676
fbshipit-source-id: 5d0cf3f03c61819e168b080afa368b1255d0419c
