Updated Upstream (Bukkit/CraftBukkit/Spigot) (#4728)

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:
30885166 Update to Minecraft 1.16.4

CraftBukkit Changes:
3af81c71 Update to Minecraft 1.16.4

Spigot Changes:
f011ca24 Update to Minecraft 1.16.4

Co-authored-by: Mariell Hoversholm <proximyst@proximyst.com>

Spigot-Server-Patches/0559-Brand-support.patch

@@ -0,0 +1,19 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: DigitalRegent <misterwener@gmail.com>
+Date: Sat, 11 Apr 2020 13:10:58 +0200
+Subject: [PATCH] Brand support
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -0,0 +0,0 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+     // Paper start - brand support
+     @Override
+     public String getClientBrandName() {
+-        return getHandle().playerConnection.getClientBrandName();
++        return getHandle().playerConnection != null ? getHandle().playerConnection.getClientBrandName() : null;
+     }
+     // Paper end
+