Add a constraint for minimal required kitchen version

[coredump]

Description

Currently there's no way on .kitchen.yml to specify what version is the lowest required one to run the tests/tools correctly.
That causes issues where new functionality are added to kitchen and used in the YAML but are ignored or return errors because someone is trying to run it on a kitchen version that doesn't support the new stuff.

Kitchen Version

Test Kitchen version 1.15.0

ChefDK Version

Chef Development Kit Version: 1.3.6
chef-client version: 12.18.31
delivery version: master (0b746cafed65a9ea1a79de3cc546e7922de9187c)
berks version: 2017-02-13T12:28:45.811234 8804] 2017-02-13T12:28:45.811394 8804] 2017-02-13T12:28:45.811504 8804] 2017-02-13T12:28:45.811603 8804] 2017-02-13T12:28:45.852202 8804] 2017-02-13T12:28:45.852492 8804] 5.6.0
kitchen version: 1.15.0
chef -v  3.01s user 0.71s

Platform Version

MacOS 10.11.6

Replication Case

• Create a kitchen YAML config using the policyfile directive under provisioner.
• Run the config using test-kitchen version 1.6.0

Kitchen will ignore policyfiles and try to converge an empty run list.

[cheeseplus]

I think this would be fairly non-invasive and could just be a warning. Something like:

---
kitchen_min_version: 1.14.0