[QUESTION] How do I set a subdirectory?

[kasbah]

Judging by #435 something is done on NPM to allow setting the subdirectory of the markdown file, so that relative image URLs resolve properly. How can I make use of this when using marky-markdown as a library?

I tried doing:

html = marky(markdown, {
  package: {repository: {url: 'https://..', directory: 'subdirectory/'}}
})

But that has no effect.