Upgrade kubernetes-client library to 6.0.0

[wolfsblu]

What this PR does / why we need it:

This PR updates the fabric8io kubernetes client library to version 6.0.0 and includes refactoring required to work with the new CustomResource API.

The purpose is to ensure compatibility with the new token exchange mechanism introduced by AWS. [1]

The BoundServiceAccountTokenVolume feature is enabled by default in Kubernetes version 1.21 and later. This feature improves the security of service account tokens by allowing workloads running on Kubernetes to request JSON web tokens that are audience, time, and key bound. Service account tokens have an expiration of one hour. In earlier Kubernetes versions, the tokens didn't have an expiration. This means that clients that rely on these tokens must refresh the tokens within an hour.

[1] https://docs.aws.amazon.com/eks/latest/userguide/service-accounts.html

Checklist

• DCO signed