QVersionNumber: apply LWG 3346 work-around

QtWebEngine builds using GCC 10.2 have hit the GCC < 10.4 problem with
containers that define both element_type and value_type, so lift the
work-around from QList to QVersionNumber, too.

Amends 2188ca2c5d.

Fixes: QTBUG-122037
Change-Id: Idb59b5325ab6308cfd7d1a5559e45a01a5802099
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

src/corelib/tools/qversionnumber.h

@@ -211,7 +211,9 @@ class QVersionNumber
 
         using iterator_category = std::random_access_iterator_tag;
         using value_type = int;
+#ifdef QT_COMPILER_HAS_LWG3346
         using element_type = const int;
+#endif
         using difference_type = qptrdiff; // difference to container requirements
         using size_type = qsizetype;      // difference to container requirements
         using reference = value_type;     // difference to container requirements