Adds release notes link in version upgrade messagebox

CURA-5348

resources/qml/Cura.qml

@@ -489,6 +489,7 @@ UM.MainWindow
                     horizontalCenterOffset: -(Math.round(UM.Theme.getSize("sidebar").width / 2))
                     top: parent.verticalCenter;
                     bottom: parent.bottom;
+                    bottomMargin:  UM.Theme.getSize("default_margin").height
                 }
             }
         }