Bump up pytorch-lightning to 2.1.2

[shreyasvinaya]

Description

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[rbharath]

Can you do a lower bound >=2.1 etc

[shreyasvinaya]

done

[rbharath]

Let's update transformers to track the latest dependency

[rbharath]

Let's make this a lower bound as well

[shreyasvinaya]

done

[rbharath]

This still needs to be bumped. Can you put up a small fix PR? I'll merge this in since it's fixed in the actual files below

[rbharath]

LGTM