Update function signature for Qt6 qHash()

Since the `qhash()` signature has changed in Qt6.

src/base/bittorrent/torrent.cpp

@@ -35,7 +35,11 @@
 
 namespace BitTorrent
 {
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+    std::size_t qHash(const TorrentState key, const std::size_t seed)
+#else
     uint qHash(const TorrentState key, const uint seed)
+#endif
     {
         return ::qHash(static_cast<std::underlying_type_t<TorrentState>>(key), seed);
     }