[qml] version number lower to 2.9 for Qt 5.9

Author: jared2020

src/main.qml

@@ -1,7 +1,7 @@
-import QtQuick 2.12
-import QtQuick.Window 2.12
-import QtQuick.Controls 2.12
-import QtQml 2.12
+import QtQuick 2.9
+import QtQuick.Window 2.9
+import QtQuick.Controls 2.9
+import QtQml 2.9
 Window {
     visible: true
     width: 640