Upstream has released updates that appear 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:
d352d965 SPIGOT-7221: Add Enemy (Entity) interface
CraftBukkit Changes:
397c5557c SPIGOT-7221: Add Enemy (Entity) interface
a0d3dfaf2 PR-1129: Fix state corruption while handling explosion damage on EntityComplexPart
d67777f8b SPIGOT-7218: Player's outer layer of skin disappears after respawn
Jake Potrebic