Bump inspec-core to 4.20.6
Bump inspec-core to 4.20.6

This pull request was triggered automatically via Expeditor when inspec-core 4.20.6 was promoted to Rubygems.

This change falls under the obvious fix policy so no Developer Certificate of Origin (DCO) sign-off is required.

chef/chef-dk,chef/chef-dk,chef/chef-dk