Add support for generating lint output

[crandles]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This adds support for rendering validation errors into a simple "lint error format" (e.g. see errorformat), with the intention of piping the lint output to reviewdog to post PR comments pertaining to any validation errors.

Which issue(s) this PR fixes:

N/A

Special notes for your reviewer:

This does pull in a new import, goccy/go-yaml. (I see it used in some other kubernetes projects)
I was unable to get the otherwise imported yaml packages to get accurate line numbers and have a way to search via field.

Does this PR introduce a user-facing change?

Adds a new output format, `--output lint`, that will render validation errors using the `%f:%l:%c: %m` 'errorformat', to be used with compatible lint tools.

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

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[crandles]

Example usage with reviewdog:

      - name: Run reviewdog
        env:
          REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          go install github.com/reviewdog/reviewdog/cmd/reviewdog@latest
          kubectl validate path/to/yaml/* -o lint | $(go env GOPATH)/bin/reviewdog -f=golint -reporter=github-pr-check -fail-level=any -tee

https://github.com/crandles/kubectl-validate-example/blob/2cd070ac781bd87eb2dd36a4c43ab942922bc6b2/.github/workflows/pr.yaml#L18-L23

Although I'd plan to craft an action for this, in the long run.

[apelisse]

I really like the direction, I'm very sad that we have to add 14k lnes of code just to be able to print filename:line:col:error. On the other hand, I realize that the current go implementation of the yaml loader doesn't give us line numbers. So at the end of the day I think this goes in the right direction.

[crandles]

Definitely agree. It's probably worth another attempt at pulling the line numbers out of one of the currently vendor-ed decoders. Perhaps I can at least share my failed attempt, if nothing else. Let me know if that would be valuable.

Happy to spend a little effort to get this right.

An alternative might be to switch yaml decoders outright, but that seemed more than necessary.

[crandles]

gopkg.in/yaml.v3, which is already imported, does support a way to decode yaml line numbers (see line/column fields): https://pkg.go.dev/gopkg.in/yaml.v3#Node, however it is not readily traversable.

There is no alternative for yaml.PathString that I can find for the gopkg.in/yaml.v3 package, so that code would need to be implemented. Given the existence of yaml anchors, you'd need a multi-step or recursive process. I believe this is when I turned to the goccy package which provided both capabilities.

[crandles]

https://pkg.go.dev/github.com/vmware-labs/yaml-jsonpath/pkg/yamlpath looks like the top alternative for easily traversing a yaml.Node