diffusers: Diffusion update breaks train_dreambooth scripts

Describe the bug

Last night I was running the dreambooth fine-tuning scripts on colab fine but today after Diffusion release 0.9.0 landed, the training script breaks.

Nothing in my code has changed except now when I launch the training script on accelerate I see the error below.

Running %pip install -qq git+https://github.com/ShivamShrirao/diffusers seems to install version Diffusion 0.9.0 and all I can think is that this has introduced a breaking change in the training script.

Is there anyway I can pin diffusers version to 0.8.1 for now when installing this github?

Reproduction

Try running the fine-tuning example notebook.

Logs

Traceback (most recent call last):
  File "train_dreambooth.py", line 822, in <module>
    main(args)
  File "train_dreambooth.py", line 458, in main
    revision=args.revision
  File "/usr/local/lib/python3.7/dist-packages/diffusers/pipeline_utils.py", line 680, in from_pretrained
    model = pipeline_class(**init_kwargs)
  File "/usr/local/lib/python3.7/dist-packages/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion.py", line 143, in __init__
    feature_extractor=feature_extractor,
  File "/usr/local/lib/python3.7/dist-packages/diffusers/pipeline_utils.py", line 149, in register_modules
    library = module.__module__.split(".")[0]
AttributeError: 'list' object has no attribute '__module__'
Traceback (most recent call last):
  File "/usr/local/bin/accelerate", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.7/dist-packages/accelerate/commands/accelerate_cli.py", line 43, in main
    args.func(args)
  File "/usr/local/lib/python3.7/dist-packages/accelerate/commands/launch.py", line 837, in launch_command
    simple_launcher(args)
  File "/usr/local/lib/python3.7/dist-packages/accelerate/commands/launch.py", line 354, in simple_launcher
    raise subprocess.CalledProcessError(returncode=process.returncode, cmd=cmd)
subprocess.CalledProcessError: Command '['/usr/bin/python3', 'train_dreambooth.py', '--pretrained_model_name_or_path=runwayml/stable-diffusion-v1-5', '--pretrained_vae_name_or_path=stabilityai/sd-vae-ft-mse', '--output_dir=/content/drive/MyDrive/stable_diffusion_weights/@potion', '--revision=fp16', '--with_prior_preservation', '--prior_loss_weight=1.0', '--seed=1337', '--resolution=512', '--train_batch_size=1', '--train_text_encoder', '--mixed_precision=fp16', '--use_8bit_adam', '--gradient_accumulation_steps=1', '--learning_rate=2e-6', '--lr_scheduler=constant', '--lr_warmup_steps=0', '--num_class_images=200', '--sample_batch_size=4', '--max_train_steps=2000', '--save_interval=250', '--save_guidance_scale=20', '--save_infer_steps=250', '--save_sample_prompt=fire @potion with dragon inside bottle, perfectly ornated, intricate details, 3d render vray, uhd, beautiful, trending', '--concepts_list=concepts_list.json', '--not_cache_latents']' returned non-zero exit status 1.

### System Info

diffusers==0.9.0
OS: Google Colab Pro (Linux)
GPU: Tesla T4

After installing the github repo, `!pip show diffusers` returns:

Name: diffusers Version: 0.9.0.dev0 Summary: Diffusers Home-page: https://github.com/huggingface/diffusers Author: The HuggingFace team Author-email: patrick@huggingface.co License: Apache Location: /usr/local/lib/python3.7/dist-packages Requires: filelock, regex, Pillow, requests, importlib-metadata, huggingface-hub, numpy Required-by: