- Padding in `SYMMETRIC` mode will cause an error if the padding size is larger than the input size, so replace `CONSTANT` with `SYMMETRIC`
- Replace `tf.reduce_mean` with `GlobalAveragePoolingxD` to reduce inference error
However, the phenomenon where the error between `AveragePool` and `GlobalAveragePool` becomes unusually large has not been corrected.

- Workaround issue with onnx_graphsurgeon aborting when using output with dtype unknown
- https://github.com/PINTO0309/onnx2tf/releases/download/1.1.28/rcnn-ilsvrc13-9.onnx
What's Changed
* Padding in `SYMMETRIC` mode will cause an error if the padding size is larger than the input size, so replace `CONSTANT` with `SYMMETRIC` by PINTO0309 in https://github.com/PINTO0309/onnx2tf/pull/127
**Full Changelog**: https://github.com/PINTO0309/onnx2tf/compare/1.5.14...1.5.15