Automate PDF generation with github actions

[ahouseholder]

Once PR #180 is resolved, we should create a github action that can be triggered in a few different ways, including:

• on-demand on a particular branch
• automatically as part of the pulll request process

This will require (at least)

• installing requirements
• running the script
• commit and add the generated PDF

[ahouseholder]

https://github.com/pandoc/pandoc-action-example seems relevant

[j---]

#180 is resolved, and #194 set the versioning as semver. I don't see particular value in calver for us. The comments in the PDF generation script introduced in #194 suggest what I'm thinking, but we still need to make a number of decisions about how to actually functionally automate this. But I don't think there are any remaining blockers for this to go forward.

[j---]

I need to look a bit more, but I think we can use https://hub.docker.com/r/pandoc/latex to pull requirements.

[ahouseholder]

As of 8da5bcb the doc/compile-pdf.sh script throws an error because the image references are to ../graphics/foo.pdf while it expects them to be in ./graphics/foo.pdf (pandoc apparently uses relative paths from where it is run from). I was able to get it to work by ln -s doc/graphics (thus making graphics appear to be a peer to doc), but that's kludgy. I'm not sure if there is a good reason for the links in the .md files to be ../graphics... instead of ./graphics - it might be as simple as a search and replace fix.

[j---]

IIRC, the reason I moved graphics to be a peer to the md_src within the doc folder was because I got some feedback that people couldn't find it to look at the images separately when it was a subfolder. But I think getting the automation working is probably more important.

[ahouseholder]

As of 8da5bcb the doc/compile-pdf.sh script throws an error because the image references are to ../graphics/foo.pdf while it expects them to be in ./graphics/foo.pdf (pandoc apparently uses relative paths from where it is run from). I was able to get it to work by ln -s doc/graphics (thus making graphics appear to be a peer to doc), but that's kludgy. I'm not sure if there is a good reason for the links in the .md files to be ../graphics... instead of ./graphics - it might be as simple as a search and replace fix.

Turns out that's covered by #181