Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
e041de28 SPIGOT-4946: Add VillagerCareerChangeEvent
CraftBukkit Changes:
fcb9f90b SPIGOT-4946: Add VillagerCareerChangeEvent
a4a2f679 SPIGOT-4987: Shulkerbox does not save empty slots
This makes it easier for downstream projects (forks) to replace the
version fetching system with their own. It is as simple as implementing
an interface and overriding the default implementation of
org.bukkit.UnsafeValues#getVersionFetcher()
It also makes it easier for us to organize things like the version
history feature.
Lastly I have updated the paper implementation to check against the site
API rather than against jenkins.