Updated Upstream (Bukkit/CraftBukkit/Spigot)
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: 1687ea8f PR-799: Adjust CreatureSpawner to allow for spawners with no mob type 08dfc6a4 PR-852: Add setMotd and setMaxPlayers 318ace0d Define SpawnerSpawnEvent
CraftBukkit Changes: 991639bc6 PR-1124: Adjust CreatureSpawner to allow for spawners with no mob type e472b6c17 PR-1184: Add setMotd and setMaxPlayers 245f2be15 Implement SpawnerSpawnEvent
Spigot Changes: 58b7c466 Move SpawnerSpawnEvent patches
Added a Server#motd(Component) method to set the motd with an adventure component. I changed the field type on MinecraftServer to adventure Component which just makes it easier to work with.
shame