* upstream/master: (24 commits)
  Automatic update of fbcode/onnx to 96c58ceeacf0f2b73d752e413e4fd78787a12da3 (pytorch#17676)
  Set the default ONNX opset to the latest stable opset (i.e., 9) (pytorch#17736)
  Add module attributes (pytorch#17309)
  - refactoring serialization of ONNX initializers to be name-based (pytorch#17420)
  ONNX Export for Max and Average Pooling in CEIL_MODE
  use flake8-mypy (pytorch#17721)
  use fp16<->fp32 intrinsic (pytorch#17496)
  Implement a Caffe2 standalone LSTM operator (pytorch#17726)
  caffe2:libtorch_cuda depends on caffe2:caffe2_gpu (pytorch#17729)
  add tensor and cost inference functions (pytorch#17684)
  ONNX Export Narrow op
  Keep the dim_type of hinted shape as BATCH if possible (pytorch#17734)
  fix different round behavior on CPU and GPU pytorch#16498 (pytorch#17443)
  Warn about memory overlaps on expanded tensors (pytorch#17576)
  fix exp fam. formula
  refactor caffe2 operator constructors - 10/9 (pytorch#17659)
  Improve ONNX symbolic for logsoftmax and softmax (pytorch#17672)
  Enable using CMD when building cpp extensions on Windows
  Do not rename net boundary inputs/outputs during ssaRewrite. (pytorch#17545)
  Reapply D14078519 (pytorch#17596)
  ...