Make data available through safetensors instead of pickle

[MikeLippincott]

          Consider finding alternative file formats to store the data found in these `.pickle` files, such as [`safetensors`](https://github.com/huggingface/safetensors) or [`onnx`](https://github.com/onnx/onnx) (I'm not certain just by looking that either would work, but I feel it'd be worthwhile to explore these or other alternatives).

Originally posted by @d33bs in #10 (comment)