safetensors dependency

[oscarnevarezleal]

I believe #84 introduced a safetensors dependency but it's not specified in requirements.txt

[hafriedlander]

It's not supposed to be required, but it is currently because train_lora_dreambooth calls save_safeloras indiscriminately. I'll add a PR soon.

My intent was that safetensors will be required to save safetensors, but not to load them (there's a pure python version), and that pytorch pickles would remain an option.

(I'd personally prefer if safetensors became the default, but that's up to @cloneofsimo and the community generally).

[hafriedlander]

#101 should fix this

[hafriedlander]

This should be fixed now #101 is merged @oscarnevarezleal - feel free to reopen if something still breaks without safetensors installed.