Track Kubernetes Channels for latest versions

[davidcollom]

This change introduces a kubernetes version checking ability, it uses the official k8s channels .txt file and defaults to "stable" for its release channel, this can be overriden with a cli flag

Things outstanding:

• Update Readme describing the feature.
• Unit test coverage.
• Use our own semver library over `github.com/Masterminds/semver/v3's (I used it more for a PoC

Stretch goals and more longer term idea's:

• Integrate into https://endoflife.date/google-kubernetes-engine when gke detected within the version string
• Look at/for EOL on AKS, EKS and other engines... where possible

[maria-reynoso]

This look great! It would be great to mention this new feature to the README.md

[davidcollom]

I think you've got some great progress here!! Just a few things to consider.

[davidcollom]

@maria-reynoso really good work on this! 👍 I'm happy for this to be merged, and we'll release a new version later this afternoon!

🙌 ❤️