add export config for starcoder2

[eaidova]

What does this PR do?

add export configuration for starcoder2 architecture. Unfortunately, there is no transformers package with this model support yet (it is part of master branch of transformers), verified locally with installing transformers from source

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?

[HuggingFaceDocBuilderDev]

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