v0.9.0-rc8

What's Changed

Documentation fixes, improvement to training quality by removing DDIM from the setup.

Fixes for optimizers and unusual configuration value combinations.

Fixes for slow writes for text embed caching being overlooked, resulting in training not finding embeds.

• fix documentation by @bghira in #296
• Fix for zero snr_gamma
• Fix subfolder support
• Add null check for subfolders by @bghira in #300
• prodigy optimizer added
• wandb fix for multigpu training
• adafactor: fix bugs, make it work like AdamW. added --adafactor_relative_step for the truly adventurous
• fix xformers / other deps
• zsnr: do not use betas from ddim sampler, instead use ddpm directly
• adamw: fix non-8bit optimizer settings for LR not being passed in
• text embed cache: add write thread progress bar, slow write warning and delay for encoding when we hit the buffer size. by @bghira in #305

Full Changelog: v0.9.0-rc7...v0.9.0-rc8