[Feature Request] Update BertScorer with oop implementation

[TheShadow29]

🚀 Feature Request

Bert Score (https://github.com/Tiiiger/bert_score) new version (0.3.1) supports oop implementation. Current vizseq uses the functional implementation which could be updated to oop implementation.

Motivation

Currently, using Bert Score in a validation loop causes re-loading the model again and again. This can be avoided with oop implementation.

Pitch

I see two solutions: (i) create a separate scorer named bert_score_oop (ii) in the current implementation of bert_score add argument whether to use oop implementation or not.

Are you willing to open a pull request?
Yes, I can send a pull request

[kahne]

@TheShadow29 Thanks very much for bringing this up! We will update shortly. Also please feel free to submit any pull request in the future.