[Move] Fix streaming with promotion

Move.cpp

@@ -1,6 +1,7 @@
 #include "Move.hpp"
 
 #include <ostream>
+#include <iostream>
 
 Move::Move(const Square &from, const Square &to, const std::optional<PieceType> &promotion)
         : mFrom(from), mTo(to), mPromotion(promotion) {
@@ -41,7 +42,7 @@ std::optional<PieceType> Move::promotion() const {
 std::ostream &operator<<(std::ostream &os, const Move &move) {
     os << move.from() << move.to();
     if (move.promotion().has_value()) {
-        os << static_cast<char>(move.promotion().value());
+        os << move.promotion().value();
     }
     return os;
 }