Upgrade onnx submodule to 85546f8c44e627f8ff1181725d03cc49f675e44f (#66427)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66427
Update the onnx submodule, so https://github.com/pytorch/pytorch/pull/66140 can land.
Test Plan: ci
Reviewed By: ezyang
Differential Revision: D31544610
fbshipit-source-id: 94831ef531bbd654a6aeb744cd53a38155848079
