Fix warning related to QSet::unite when building against Qt 5.15

Author: jcfr

src/PythonQtClassInfo.cpp

@@ -562,7 +562,7 @@ QStringList PythonQtClassInfo::memberList()
     }
   }
 
-#if QT_VERSION >= 0x060000
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
   QSet<QString> set(l.begin(), l.end());
   return set.values();
 #else

src/PythonQtClassWrapper.cpp

@@ -465,7 +465,7 @@ static PyObject *PythonQtClassWrapper_getattro(PyObject *obj, PyObject *name)
 
     auto members = wrapper->classInfo()->memberList();
     auto properties = wrapper->classInfo()->propertyList();
-#if QT_VERSION >= 0x060000
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
     QSet<QString> completeSet(members.begin(), members.end());
     completeSet.unite(QSet<QString>(properties.begin(), properties.end()));
 #else