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

Please note that this build includes changes to meet upstreams
requirements for nullability annotations. While we aim for a level of
accuracy, these might not be 100% correct, if there are any issues,
please speak to us on discord, or open an issue on the tracker to
discuss.

Bukkit Changes:
9a6a1de3 Remove nullability annotations from enum constructors
3f0591ea SPIGOT-2540: Add nullability annotations to entire Bukkit API

CraftBukkit Changes:
8d8475fc SPIGOT-4666: Force parameter in HumanEntity#sleep
8b1588e2 Fix ExplosionPrimeEvent#setFire not working with EnderCrystals
39a287b7 Don't ignore newlines in PlayerListHeader/Footer

Spigot Changes:
cf694d87 Add nullability annotations

Spigot-API-Patches/Allow-setting-the-vex-s-summoner.patch

@@ -5,29 +5,37 @@ Subject: [PATCH] Allow setting the vex's summoner
 
 
 diff --git a/src/main/java/org/bukkit/entity/Vex.java b/src/main/java/org/bukkit/entity/Vex.java
-index 7b9b21e5..23a15f8f 100644
+index 6b61c4ab7..c34a3ea7b 100644
 --- a/src/main/java/org/bukkit/entity/Vex.java
 +++ b/src/main/java/org/bukkit/entity/Vex.java
+@@ -0,0 +0,0 @@
+ package org.bukkit.entity;
+ 
++import org.jetbrains.annotations.Nullable;
++
+ /**
+  * Represents a Vex.
+  */
 @@ -0,0 +0,0 @@ public interface Vex extends Monster {
+      * @param charging new state
       */
      void setCharging(boolean charging);
- 
++
 +    // Paper start
-     /**
--     * @return What Entity (most likely an Evoker, but not guaranteed) summoned this Vex
++    /**
 +     * Get the Mob that summoned this vex
 +     *
 +     * @return Mob that summoned this vex
 +     */
++    @Nullable
 +    Mob getSummoner();
 +
 +    /**
 +     * Set the summoner of this vex
 +     *
 +     * @param summoner New summoner
-      */
--    Mob getSummoner(); // Paper
-+    void setSummoner(Mob summoner);
++     */
++    void setSummoner(@Nullable Mob summoner);
 +    // Paper end
  }
 --