Set the fake offline UUID on lowest priority (-> as soon as possible)

Then every plugin listening on priority level higher than lowest can see that fake UUID

This also fixes race conditions for plugins listening on the same priority as FastLogin before (->low)
(Fixes #167)

bungee/src/main/java/com/github/games647/fastlogin/bungee/listener/PlayerConnectionListener.java

@@ -52,7 +52,7 @@ public class PlayerConnectionListener implements Listener {
         ProxyServer.getInstance().getScheduler().runAsync(plugin, asyncPremiumCheck);
     }
 
-    @EventHandler(priority = EventPriority.LOW)
+    @EventHandler(priority = EventPriority.LOWEST)
     public void onLogin(LoginEvent loginEvent) {
         if (loginEvent.isCancelled()) {
             return;