set minimal required inspec version

Signed-off-by: Christoph Hartmann <chris@lollyrock.com>

Author: chris-rock

README.md

@@ -12,7 +12,7 @@ InSpec is an open-source run-time framework and rule language used to specify co
 
 ## Requirements
 
-* at least [InSpec](http://inspec.io/) version 1.38.8
+* at least [InSpec](http://inspec.io/) version 2.3.23
 * Docker 1.13+
 
 ### Platform

inspec.yml

@@ -6,6 +6,7 @@ copyright_email: hello@dev-sec.io
 license: Apache-2.0
 summary: An InSpec Compliance Profile for the CIS Docker Benchmark
 version: 2.1.0
+inspec_version: '>= 2.3.23'
 attributes:
   - name: container_user
     required: false