[dreambooth] link to bitsandbytes readme for installation  (#1229)
[dreambooth] link to bitsandbytes readme for installation  (#1229)

* add 'conda install cudatoolkit' to dreambooth 'training on 16GB' example 

fixes https://github.com/huggingface/diffusers/issues/1207

* Apply suggestions from code review

Co-authored-by: Suraj Patil <e55124f2bc241ddfef100229e12a1887b326eb73@gmail.com>
huggingface/diffusers