Lakshmi Bashyam

Results 2 issues of Lakshmi Bashyam

This PR adds xtransformer as an optional dependency, incorporating minor changes and updating the backend implementation to align with the latest Annif version, building on the previous xtransformer PR #540

enhancement

The codebase currently imports `AdamW` from `transformers`: ```python from transformers import AdamW ``` However, this import has been **deprecated and removed** in recent Transformer versions (as noted in Hugging Face...

bug