[Suggestion] Use CSL-JSON for doi2cite in place of Bibtex

[the-solipsist]

doi2cite currently uses Bibtex (application/x-bibtex):
https://github.com/pandoc/lua-filters/blob/master/doi2cite/doi2cite.lua#L105

Given that bibliography details can be downloaded in CSL-JSON format as well, e.g.:

curl -LH "Accept: application/vnd.citationstyles.csl+json" https://doi.org/10.1126/science.169.3946.635

perhaps that should be preferred since it is citeproc's native format?

[korintje]

@the-solipsist
I'm sorry for not noticing the suggestion for a long time.
Honestly I did not know CSL-JSON format, but it seems to be preferred.
I will modify the filter later. Thanks for the suggestion!