[Feature Request] Check for presence of CODEOWNERS file

[emtunc]

Branch Protection is a good first step towards ensuring code is approved by a member of the organisation. If we are to take this to the next level then we should be checking for a valid CODEOWNERS file (presence of the file is sufficient to begin with).

I would like to see an issue raised when a CODEOWNERS file is missing in the root of a repository.

It's not a check that could have the "fix" action applied to it but that should be okay.

This could possibly sit under the branch_protection.yaml config as you would typically only use CODEOWNERS as part of a Branch Protection stategy.