Update ONNX submodule from ONNX 1.13.1 with Protobuf 4.21 updates (#96138)
~Test ONNX 1.13.1 package which was built with Protobuf v21. onnx-test-protobufv21 package was created by this PR: https://github.com/onnx/onnx/pull/4973, which was based with the rel-1.13.1 release branch (which is what PyTorch is using now).~ Update ONNX submodule from https://github.com/onnx/onnx/tree/1.13.1-protobuf4.21, which was created with rel-1.13.1 branch with updated for Protobuf 4.21. Please note that PyTorch should still be able to build ONNX from source by Protobuf 3 with the same source code.
BTW, https://github.com/onnx/onnx/pull/4956/files. is the PR targeting ONNX's main branch.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96138
Approved by: https://github.com/kit1980, https://github.com/BowenBao
