Extend support to transformers v4.31

[adrianeboyd]

Description

Restrict backwards compatibility test to transformers<4.31.

Types of change

?

Checklist

• I confirm that I have the right to submit this contribution under the project's MIT license.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.

[adrianeboyd]

In most relevant cases there is already a general warning saying it might not work, so I think it could be okay to leave it at that.

I think we could put this change in v1.3.0 so it wouldn't affect any existing saved trf models with spacy_transformers>=1.2.0,<1.3.0.

[adrianeboyd]

I think we can add a more informative warning and then still make this change as v1.3.0 so there aren't any surprises with existing packaged models.

[adrianeboyd]

I'll just go ahead and do this as v1.3.0 in case people need newer versions of transformers.