Update the F: line after the Meson refactor.

Fixes: 1bb4cb1c..73362fc0 ("default-configs: ...")
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20201117114656.1222555-1-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>