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:
7634491f Added Entity#setRotation.
CraftBukkit Changes:
0e1cea5a Added Entity#setRotation.
Allows you to return the SpawnReason for why an Entity Spawned
Pre existing entities will return NATURAL if it was a non
persistenting Living Entity, SPAWNER for spawners,
or DEFAULT since data was not stored.
