Fix content negotiate for schema 3.x dois

[kjgarza]

Purpose

User are unable to get bibtex formatted metadata for dois with kernel-3 schema.

In Bolognese metadata regenerated every time for these DOIs but instead of taking the value of the regenerated xml bolognese takes it from the original file.

closes: https://github.com/datacite/datacite/issues/1024

Approach

we get the kernel version from the regenerated xml.

Open Questions and Pre-Merge TODOs

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Learning

Status

• [x] Ready for Review

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

[kjgarza]

@mfenner But that’s not how the bug occurred. Look at the related bug issue. The error occurs when content negotiating bibtex from a doi that has schema 3 metadata. Therefore the metadata conversion would be from datacite_json to bibtex.