fix: use macros from macros.kf5 instead of custom code

qqc2-desktop-style.spec

@@ -10,7 +10,7 @@ Summary: QtQuickControls2 style for consistency between QWidget and QML apps
 License: (LGPLv3 or GPLv3) and LGPLv2+
 URL:     https://invent.kde.org/frameworks/%{framework}
 
-%global majmin %(echo %{version} | cut -d. -f1-2)
+%global majmin %majmin_ver_kf5
 %global stable %stable_kf5
 Source0: http://download.kde.org/%{stable}/frameworks/%{majmin}/%{framework}-%{version}.tar.xz