Current builds are failing

[dsblank]

! LaTeX Error: File `unicode-math.sty' not found.

https://travis-ci.com/github/jupyter4edu/jupyter-edu-book/builds/216648669

Anyone know what changed; how to fix?

[mandli]

Other than this seems to have been an issue for awhile. I am not even certain why the book would depend on unicode-math given what the repos states that it is for.