commit cacc0b2678 ("CI: Move to latest container image") updated the
docker container image.
Reflect the change in the documentation.
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>