Removed depracated ruby client library

The 'kubr' gem has last been updated 7 years ago. It doesn't provide the required modern functionalities. The documentation consists of one code example and that's it. It's inclusion in this list only wastes time of Ruby on Rails developers because no sane person would chose it.

Author: Anakin100100

content/en/docs/reference/using-api/client-libraries.md

@@ -71,7 +71,6 @@ their authors, not the Kubernetes team.
 | Python               | [github.com/tomplus/kubernetes_asyncio](https://github.com/tomplus/kubernetes_asyncio) |
 | Python               | [github.com/Frankkkkk/pykorm](https://github.com/Frankkkkk/pykorm) |
 | Ruby                 | [github.com/abonas/kubeclient](https://github.com/abonas/kubeclient) |
-| Ruby                 | [github.com/Ch00k/kuber](https://github.com/Ch00k/kuber) |
 | Ruby                 | [github.com/k8s-ruby/k8s-ruby](https://github.com/k8s-ruby/k8s-ruby) |
 | Ruby                 | [github.com/kontena/k8s-client](https://github.com/kontena/k8s-client) |
 | Rust                 | [github.com/clux/kube-rs](https://github.com/clux/kube-rs) |