Fix missing header after stdlib update

src/Battling/History/HistoryHolder.hpp

@@ -1,10 +1,11 @@
 #ifndef CREATURELIB_HISTORYHOLDER_HPP
 #define CREATURELIB_HISTORYHOLDER_HPP
 
+#include <functional>
 #include <utility>
 #include "../../Library/Exceptions/CreatureException.hpp"
-#include "HistoryElements/HistoryElement.hpp"
 #include "HistoryElements/DamageHistory.hpp"
+#include "HistoryElements/HistoryElement.hpp"
 
 template <class T>
 concept HistoryElementType = std::is_base_of<CreatureLib::Battling::HistoryElement, T>::value;