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:
fd28180e #479: Add LivingEntity#attack, LivingEntity#swingMainHand, LivingEntity#swingOffHand
ae72ba3a SPIGOT-5591: Allow concurrent potion effects
CraftBukkit Changes:
3d61a853 Fix formatting in CraftLivingEntity
f7ab3055#633: Add LivingEntity#attack, LivingEntity#swingMainHand, LivingEntity#swingOffHand
d5ef2eab SPIGOT-5591: Allow concurrent potion effects
25a9a9ff SPIGOT-5592: Custom ChunkGenerator can cause bugged dirt
3f6d0de9 Make it clear in error messages that api-version above 1.13 is also supported
