Null check for set health.

.gitlab-ci.yml

@@ -4,7 +4,7 @@ stages:
 variables:
     name: "UltimateStacker"
     path: "/builds/$CI_PROJECT_PATH"
-    version: "1.5.9"
+    version: "1.5.10"
 
 build:
   stage: build

src/main/java/com/songoda/ultimatestacker/entity/EntityStack.java

@@ -184,6 +184,7 @@ public class EntityStack {
     }
 
     public void updateHealth(LivingEntity entity) {
+        if (entity == null) return;
         entity.setHealth(Setting.STACK_ENTITY_HEALTH.getBoolean()
                 && !this.health.isEmpty() ? this.health.removeFirst() : entity.getMaxHealth());
     }