Fix REntity

SpigotCore_Main/src/de/steamwar/entity/REntity.java

@@ -350,7 +350,7 @@ public class REntity {
     }
 
     private static final Class<?> metadataPacket = Reflection.getClass("{nms.network.protocol.game}.PacketPlayOutEntityMetadata");
-    private static final Reflection.FieldAccessor<Integer> metadataEntity = Reflection.getField(metadataPacket, int.class, 0);
+    private static final Reflection.FieldAccessor<Integer> metadataEntity = Reflection.getField(metadataPacket, int.class, Core.getVersion() > 18 ? 1 : 0);
     private static final Reflection.FieldAccessor<List> metadataMetadata = Reflection.getField(metadataPacket, List.class, 0);
 
     protected Object getDataWatcherPacket(Object... dataWatcherKeyValues) {