CODEOWNERS: [ONNX] remove @shubhambhokare1; add @abock (#85476)
Add me to field notifications for the ONNX team, replacing @shubhambhokare1.
cc @malfet
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85476
Approved by: https://github.com/kit1980, https://github.com/AllenTiTaiWang
