welcome screnn: adjust color of vertical separator

Change-Id: Id607064c522f9d88a981a2b2f7ff4fd75d04ead4
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

share/qtcreator/welcomescreen/widgets/HeaderItemView.qml

@@ -60,7 +60,7 @@ Item {
     }
     Rectangle {
         height: 1
-        color: "#000000"
+        color: "#a09c90"
         anchors.top: header.bottom
         width: parent.width
     }