Clean up disk sapce during docker image build for transformers-pytorch-gpu

[ydshieh]

What does this PR do?

PyTorch pipeline CI job start to fail due to

 ImportError: accelerate>=0.20.3 is required for a normal functioning of this module, but found accelerate==0.20.2.
Try: pip install transformers -U or pip install -e '.[dev]' if you're working with git main

The root cause is: docker image for this job failed to build due to disk space issue

RROR: Could not install packages due to an OSError: [Errno 28] No space left on device

As usual, let's us save Space!

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[amyeroberts]

🧹 🧹 🧹 🧹 🧹

Thanks for fixing and cleaning up space!