CI: Add reviewdog-k8s

[rinx]

Description:

• Add kubeval-conflint to detect invalid type field in k8s manifests.
• Add kubelinter (without reviewdog)

Related Issue:

nothing

How Has This Been Tested?:

nothing

Environment:

• Go Version: 1.15.2
• Docker Version: 19.03.8
• Kubernetes Version: 1.18.2
• NGT Version: 1.12.1

Types of changes:

• Bug fix [type/bug]
• New feature [type/feature]
• Add tests [type/test]
• Security related changes [type/security]
• Add documents [type/documentation]
• Refactoring [type/refactoring]
• Update dependencies [type/dependency]
• Update benchmarks and performances [type/bench]
• Update CI [type/ci]

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

Checklist:

• I have read the CONTRIBUTING document.
• I have checked open Pull Requests for the similar feature or fixes?
• I have added tests and benchmarks to cover my changes.
• I have ensured all new and existing tests passed.
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly.

[vdaas-ci]

[CHATOPS:HELP] ChatOps commands.

• 🙆‍♀️ /approve - approve
• 💌 /changelog - add changelog comment
• 🍱 /format - format codes and add licenses
• ✅ /gen-test - generate test codes
• 🏷️ /label - add labels
• ⏪ /rebase - rebase master

[github-actions]

_{reported by reviewdog 🐶}
Invalid type. Expected: [integer,null], given: string

[kpango]

LGTM

But, I think it's better to integrate kubeval with https://github.com/stackrox/kube-linter
kubeval finds yaml mistake, but kube-linter can find bad practice about k8s yaml, so I recommend adding kube-linter to job

[rinx]

aha, i'll revise this PR to integrate with it. thanks.
after finished, i'll change back to open again. @kpango

[rinx]

https://github.com/vdaas/vald/runs/1378253698?check_suite_focus=true
kubelinter is really noisy, we can exclude some check rules from the defaults like "unset-cpu-requirements", "unset-memory-requirements".

[rinx]

@kpango ready again.

[kpango]

LGTM