#863: Add LivingEntity#isClimbing

By: Martoph <sager1018@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java

@@ -606,6 +606,11 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
         return getHandle().isSleeping();
     }
 
+    @Override
+    public boolean isClimbing() {
+        return getHandle().isClimbing();
+    }
+
     @Override
     public AttributeInstance getAttribute(Attribute attribute) {
         return getHandle().craftAttributes.getAttribute(attribute);