Make QListWidget::mimeData compatible with Qt 6

src/covermanager/albumcovermanagerlist.h

@@ -24,9 +24,9 @@
 #include "config.h"
 
 #include <QObject>
+#include <QString>
 #include <QList>
 #include <QListWidget>
-#include <QString>
 
 class QWidget;
 class QMimeData;
@@ -43,7 +43,12 @@ class AlbumCoverManagerList : public QListWidget {
   void set_cover_manager(AlbumCoverManager *manager) { manager_ = manager; }
 
  protected:
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+  QMimeData *mimeData(const QList<QListWidgetItem*> &items) const override;
+#else
   QMimeData *mimeData(const QList<QListWidgetItem*> items) const override;
+#endif
+
   void dropEvent(QDropEvent *event) override;
 
  private: