Pin accelerate to fix CI failures/issues

.github/workflows/nv-accelerate-v100.yml

@@ -47,6 +47,7 @@ jobs:
  unset TORCH_CUDA_ARCH_LIST # only jit compile for current arch
  git clone https://github.com/huggingface/accelerate
  cd accelerate
+ git checkout ae9cb6e4db6f81fd18148c2cc67d72b903d81a46
  git rev-parse --short HEAD
  # installing dependencies
  pip install .[testing]