make plugin compile again after latest core update

plugin-modules/Core/src/com/songoda/epicbosses/EpicBosses.java

@@ -211,6 +211,10 @@ public class EpicBosses extends SongodaPlugin implements IReloadable {
         ServerUtils.get().logDebug("Loaded all fields and managers, saved messages and plugin is initialized and ready to go. (took " + (System.currentTimeMillis() - beginMs) + "ms).");
     }
 
+    @Override
+    public void onDataLoad() {
+    }
+
     @Override
     public List<Config> getExtraConfig() {
         return new ArrayList<>();