Fix dependencies for source file generated through rcc

There was a missing dependency rule which would cause the generated cpp
file to not be updated when changes were made to a qrc file generated
through add_qt_resource().

Change-Id: I9544c2fb6cf49529913f731b8fb6fc524d65e40c
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

cmake/QtBuild.cmake

@@ -2600,7 +2600,7 @@ function(add_qt_resource target resourceName)
                        COMMAND "${QT_CMAKE_EXPORT_NAMESPACE}::rcc"
                        ARGS --name "${newResourceName}"
                            --output "${generatedSourceCode}" "${generatedResourceFile}"
-                       DEPENDS ${resources}
+                       DEPENDS ${resources} ${generatedResourceFile}
                        COMMENT "RCC ${newResourceName}"
                        VERBATIM)