Add support for quantized slice conversion (#30498)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30498
Updated Int8SliceOp to accept dim, start and end index similar to Pytorch.
Test Plan:
python test/onnx/test_pytorch_onnx_caffe2_quantized.py TestQuantizedOps.test_slice
Imported from OSS
Differential Revision: D18740519
fbshipit-source-id: 2313f37a4936edb150ce04911b241e591e191801
