"'vignetteInfo' is not an exported object from 'namespace:tools'" for R Version 3.5 and 3.4

I have a CRON job scheduled for my repo, and I haven’t pushed any recent changes in a month. Recently the build for R version 3.4 and 3.5 started failing. The remaining version are building as expected.

https://travis-ci.com/github/dachosen1/formulaic/builds/170607214

If you changed nothing, most probably, some dependencies and/or external resources changed.

In this case, it’s a problem with rmarkdown v2.2, it started using an API that’s only available since R 3.6:

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