Revert "Merge branch 'hustewart-forked-kubeclient-dep-update' into 'master'"

What does this MR do and why?

Usage of git: https://github.com is discouraged because :

1. We do not want to introduce another point of failure when installing (github.com)
2. The presence of a dependency to a personal repo (even that of a GitLab team member) may not look right to our customers

I propose as an alternative, we vendor the gem as detailed in https://docs.gitlab.com/ee/development/gemfile.html#gitlab-created-gems in a follow-up MR => !107171 (merged)

Reverts !106419 (merged)

Screenshots or screen recordings

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How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.