chore: update default konnectivity version

[avorima]

With the EOL of 1.27, apiserver-network-proxy installation should use the minor versions of their cluster's version.
So the recommended konnectivity version for a 1.29.X Kubernetes cluster is 0.29.Y.

See: https://github.com/kubernetes-sigs/apiserver-network-proxy?tab=readme-ov-file#versioning-and-releases

Increase the default version for konnectivity to v0.28.6, which corresponds to the next EOL Kubernetes minor version.

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[prometherion]

Thanks for catching up, it would be cool if we could automatically determine the Konnectivity version according to the Kubernetes one unless the user specifies one.

We could address this in a different PR, thanks anyway for bumping up!

[avorima]

Thanks for catching up, it would be cool if we could automatically determine the Konnectivity version according to the Kubernetes one unless the user specifies one.

We could address this in a different PR, thanks anyway for bumping up!

Yes, I was thinking the same thing. A simple default would be using v0.29.0 for v1.29.X, v0.30.0 for v1.30.X and so on.

[prometherion]

Thanks, tracking a future request with #494.