Add option to explicitly include or exclude specific nodes

[ttarczynski]

Pull Request Checklist

Is this in reference to an existing issue?

General

• [x] Update Changelog following the conventions laid out at here

• [x] Update README with any necessary configuration snippets

• [ ] Binstubs are created if needed

• [x] RuboCop passes

• [x] Existing tests pass

New Plugins

N/A

Purpose

Adds the ability to explicitly include or exclude nodes in check-kube-pods-pending/restarting/running, check-kube-nodes-ready. It is useful when some nodes are intentionally NotReady but we still need to check what's running on other nodes. I've followed the pattern used in:

• 37 "ability to explicitly include namespaces"

Known Compatibility Issues

[majormoses]

Thanks for your contribution to Sensu plugins! Without people like you submitting PRs we couldn't run the project. I will review it shortly.

[ttarczynski]

@majormoses thank you for the review!

• I've applied changes in options naming and docs
• will get back to this next week and try to follow your advise on lib and the exclude logic

[majormoses]

Apologies in advance if next week I do not respond quickly as I will be traveling for work

[ttarczynski]

@majormoses i've just applied the remaining fixes:

• moved the should_exclude_node function to a lib
• changed the logic when a node is in both include and exclude lists and added info in docs

[majormoses]

Thanks, I will review this evening.

[majormoses]

released: https://rubygems.org/gems/sensu-plugins-kubernetes/versions/3.1.0