codefresh validate should return non-zero exit codes on validation

[todaywasawesome]

Codefresh CLI’s codefresh validate returns 0 even when the file is not valid. It should return non-zero so I can use it in continuous integration without having to do fancy grep-ing.

Discussion https://community.codefresh.io/t/codefresh-cli-validate-returns-0-even-when-invalid/250

[RothAndrew]

Thanks @todaywasawesome !

[kostis-codefresh]

Should be fixed by PR #368