Support for op_type "ConvTranspose"

[jnnks]

Importing YOLOv6-nano fails with:

** (ArgumentError) unsupported "ConvTranspose"
    (axon_onnx 0.1.0) lib/axon_onnx/deserialize.ex:1611: AxonOnnx.Deserialize.recur_nodes/2
    (elixir 1.13.4) lib/enum.ex:2396: Enum."-reduce/3-lists^foldl/2-0-"/3
    (axon_onnx 0.1.0) lib/axon_onnx/deserialize.ex:44: AxonOnnx.Deserialize.graph_to_axon/2
    (axon_onnx 0.1.0) lib/axon_onnx/deserialize.ex:27: AxonOnnx.Deserialize.to_axon/2
    (stdlib 3.17.1) erl_eval.erl:685: :erl_eval.do_apply/6
    (elixir 1.13.4) lib/code.ex:404: Code.validated_eval_string/3

Axon has support for ConvTranspose: https://elixir-nx.github.io/axon/Axon.html#conv_transpose/3
This PR will bridge the gap.

[jnnks]

I am closing this, as I will have no time in the foreseeable future to tackle this feature