samples: check if update is needed

Add a ct-ng action to check if samples needs being updated.
This will be usefull when the config options change.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

reporter_name="Yann E. MORIN"

reporter_url="http://ymorin.is-a-geek.org/"

reporter_comment="Toolchain for the Raspberry Pi, with hard-float."