Updated Upstream (Bukkit/CraftBukkit)

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:
218294b1 PR-743: Support setting individual Wither head targets

CraftBukkit Changes:
d48f2d1a PR-1047: Support setting individual Wither head targets
518f1bee SPIGOT-6948: Motion from Explosion after Respawn
f3c7a6ac SPIGOT-7019: Add yaw in World#getSpawnLocation

patches/server/Missing-Entity-Behavior-API.patch

@@ -568,8 +568,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftWither.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftWither.java
 @@ -0,0 +0,0 @@ public class CraftWither extends CraftMonster implements Wither, com.destroystok
-     public BossBar getBossBar() {
-         return this.bossBar;
+         Entity target = this.getHandle().getLevel().getEntity(entityId);
+         return (target != null) ? (LivingEntity) target.getBukkitEntity() : null;
      }
 +
 +    // Paper start