Hi, thanks for the amazing plugin!

I occasionally need to pass in --variables key=val1 to render my PDF document. However, it seems we don't support nested maps right now.

I am posting the Pandoc documentation about the options here for reference: https://pandoc.org/MANUAL.html#general-writer-options-1.

I saw some other structures that need nested structure support, and I think it would be great to have this.