Updated Upstream (Bukkit/CraftBukkit/Spigot)

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

Developers!: You will need to clean up your work/Minecraft/1.13.2 folder
for this

Also, restore a patch that was dropped in the last upstream

Bukkit Changes:
279eeab3 Fix command description not being set
96e2bb18 Remove debug print from SyntheticEventTest

CraftBukkit Changes:
d3ed1516 Fix dangerously threaded beacons
217a293d Don't relocate joptsimple to allow --help to work.
1be05a21 Prepare for imminent Java 12 release
a49270b2 Mappings Update
5259d80c SPIGOT-4669: Fix PlayerTeleportEvent coordinates for relative teleports

Spigot Changes:
e6eb36f2 Rebuild patches

Spigot-Server-Patches/Fix-client-rendering-skulls-from-same-user.patch

@@ -12,7 +12,7 @@ This allows the client to render multiple skull textures from the same user,
 for when different skins were used when skull was made.
 
 diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
-index 8f2b0742d..e0091358a 100644
+index 713977e3c..91a9f1bbb 100644
 --- a/src/main/java/net/minecraft/server/ItemStack.java
 +++ b/src/main/java/net/minecraft/server/ItemStack.java
 @@ -0,0 +0,0 @@ public final class ItemStack {