[train] Bump accelerate version (#36369)

Resolves failing huggingface example on master.

Signed-off-by: Kai Fricke <kai@anyscale.com>

python/requirements/ml/requirements_train.txt

@@ -19,7 +19,7 @@ transformers==4.19.1; python_version > '3.6'
 # We need accelerate>=0.17.0 for AccelerateTrainer to work (not available on py 3.6)
 # If changing the version here, also change it in AccelerateTrainer docstring
 accelerate==0.5.1; python_version <= '3.6'
-accelerate==0.17.1; python_version > '3.6'
+accelerate==0.20.3; python_version > '3.6'
 # Tracking issue: https://github.com/ray-project/ray/issues/34399
 deepspeed==0.8.3; python_version > '3.6'
 datasets==2.0.0