fix: use `ImageField<never>` rather than `ImageField<null>`

[angeloashmore]

Types of changes

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

Description

This PR changes the generated type for Image fields without thumbnails to use the latest @prismicio/types recommendation.

• OLD: ImageField<null>
• NEW: ImageField<never>

null will continue to work, but it is deprecated in @prismicio/types. Similarly, never was supported in previous versions of @prismicio/types, but it was not the recommended API. That recommendation has changed.

See https://github.com/prismicio/prismic-types/pull/46 for more details.

Checklist:

• [ ] My change requires an update to the official documentation.
• [x] All TSDoc comments are up-to-date and new ones have been added where necessary.
• [x] All new and existing tests are passing.

[github-actions[bot]]

size-limit report 📦

Path	Size
dist/index.js	1.07 MB (-0.01% 🔽)
dist/index.cjs	1.08 MB (-0.01% 🔽)