### Bug description

The field bibliography now must be validated as a string, but existing filters for Pandoc sometimes use other types. Example:

```
bibliography:
  primary: test/primary.bib
  secondary: test/secondary.bib
```

This is the case of the [multi bib filter](https://github.com/pandoc-ext/multibib). Please see: https://github.com/pandoc-ext/multibib/issues/1 

Is there any way to bypass this validation?

Thank you.



### Checklist

- [ ] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [ ] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [ ] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [ ] Please document the operating system you're running. If on Linux, please provide the specific distribution.
2023-01-28T22:16:26Z
bcdavasconcelos
closed
Strict YAML validation collides with existing lua filters for Pandoc
https://github.com/quarto-dev/quarto-cli/issues/4139