Change mixlib-shellout pattern to allow 3.x
Change mixlib-shellout pattern to allow 3.x

There is an incompatibility with chef >= 15.x,
omnibus >=7.0 and license_scout >=1.x where
they run into dependency incompatibilities
due to chef requiring mixlib-shellout 3.x
while license_scout has it pinned to 2.2.

Signed-off-by: Matthias Kaeppler <1a3659dffc93f42bb6c41a41fe8e25de37af728f@gmail.com>

chef/license_scout,chef/license_scout