Add x$references to bibliography

[peterdesmet]

Aims to fix #121. The EML object returned by write_eml() is correct:

library(camtrapdp)
x <- example_dataset()
x$references <- c("ref 1", "ref 2")
eml <- write_eml(x, ".")
#> 
#> ── Writing file ──
#> 
#> • './eml.xml'
eml$additionalMetadata
#> $metadata
#> $metadata$gbif
#> $metadata$gbif$bibliography
#> $metadata$gbif$bibliography$citation
#> [1] "ref 1"
#> 
#> $metadata$gbif$bibliography$citation
#> [1] "ref 2"

^{Created on 2025-06-04 with reprex v2.1.1}

But the XML file doesn't seem to like that the elements have the same name and coverts it to:

<additionalMetadata>
    <metadata>
      <gbif>
        <bibliography>
          <citation>ref 1</citation>
          <citation.1>ref 2</citation.1>
        </bibliography>
      </gbif>
    </metadata>
  </additionalMetadata>

I'm not sure where that occurs (EML::write_eml() or underlying xml2::write_xml()) and how to resolve this. See also ropensci/EML#351

[peterdesmet]

The root cause is jsonlite::toJSON() in this line https://github.com/ropensci/emld/blob/d12da6660f154cec35adc5a48aa32d8cc4fb590f/R/as_xml.R#L129

library(jsonlite)
ref <- list(
  citation = "ref 1",
  citation = "ref 2"
)

jsonlite::toJSON(ref)
#> {"citation":["ref 1"],"citation.1":["ref 2"]}

^{Created on 2025-06-04 with reprex v2.1.1}

[peterdesmet]

Blocked by ropensci/emld#72