ANN: pandoc 3.1

[John MacFarlane]

I'm pleased to announce the release of pandoc 3.1,
available in the usual places:

Binary packages & changelog:
https://github.com/jgm/pandoc/releases/tag/3.1

Source & API documentation:
http://hackage.haskell.org/package/pandoc-3.1

This version adds a new option --chunk-template, giving the user more
control over the filenames in chunked HTML output.

There are several other bug fixes and minor improvements.

API changes:

* Text.Pandoc.App: Add optChunkTemplate constructor to Opt.
* Text.Pandoc.Options: add writerChunkTemplate constructor to WriterOptions.
* Text.Pandoc.Chunks: add Data, Typeable, Generic, ToJSON, FromJSON
instances for PathTemplate.

Thanks to all who contributed, especially new contributors
Daniel Kessler, Martin Joerg, and Stephen Altamirano.