error converting BLOOM safetensors -> gguf (model_* vs, model-*)

[hpcpony]

Looks like convert-hf-to-gguf.py make the assumption that model part files are named "model-*" when BLOOM (https://huggingface.co/bigscience/bloom/tree/main) uses the convention "model_*". Looks like there's a similar issue with "pytorch_model-*" vs. BLOOM's "pytorch_model_*".