Update pandoc

[fcasson]

The pandoc version in default ubuntu repositories is a bit outdated. Can it be updated by installing from the tarball or the debian package on pandoc pages ?

https://pandoc.org/installing.html

[humitos]

Hi @fcasson! We are building a new Docker image based on Ubuntu 20.04 LTS. It will come with pandoc 2.5 (https://packages.ubuntu.com/focal/pandoc)

From their GitHub repository releases, I can see that 2.14.2 is the latest: https://github.com/jgm/pandoc/releases

However, we are moving away from installing package versions that are not installed via APT in our images.

As a hacky workaround, you could download and install the tarball by yourself by adding the required commands in your conf.py. In the future, this will be possible by using build.pre_build key from the config file. Once the Future Builders are implemented (readthedocs/readthedocs.org#8190)

[astrojuanlu]

Or, you can install it with conda from conda-forge, which will pull the latest version https://github.com/conda-forge/pandoc-feedstock

[humitos]

It's now possible to use the image Ubuntu 22.04 LTS which should come with a more updated pandoc version.