Update find_optimizer_opset_version_updates_required.py to use the ONNX headers to determine the latest opset.

[skottmckay]

Description: Use the onnx headers to find the latest opset for each operator. This allows the script to detect optimizers with graph_utils::IsSupportedOptypeVersionAndDomain calls that need updating when run during the update of the onnx commit id. Without this change issues are not detected until a new kernel is registered.

Motivation and Context Detect optimizers that need updates as part of the ONNX update process.