Image captioning tutorial - `transformers` library with JAX

[8bitmp3]

The Image captioning tutorial uses transformers.FlaxViTForImageClassification.

As per huggingface/transformers PR 38758 (warning messages):

TensorFlow and JAX classes are deprecated and will be removed in Transformers v5. We
recommend migrating to PyTorch classes or pinning your version of Transformers.

@jakevdp