interface {} is []interface {}, not []map[string]interface {}

[eyalzek]

If a validator doesn't find at least one violation, it'll result in an error:
interface {} is []interface {}, not []map[string]interface {}

This can be reproduced easily by modifying the (sample)[https://github.com/cloud66-oss/copper/blob/2.0.0/samples/sample.yml] by either of the following:

• remove the Deployment object entirely from the yaml
• change latest into any other string