Robustify kubectl download commands
Robustify kubectl download commands

`{K8S_VERSION}` gets auto-replaced with `\{K8S_VERSION\}` when pasting into a terminal. Encapsulating in double quotes avoids this.
rata/kubernetes.github.io,AlainRoy/alainroy.github.io,erictune/erictune.github.io,ronaldpetty/kubernetes.github.io,rata/kubernetes.github.io,aidevops/kubernetes.github.io,AlainRoy/alainroy.github.io,aidevops/kubernetes.github.io,rata/kubernetes.github.io,aidevops/kubernetes.github.io,erictune/erictune.github.io,rata/kubernetes.github.io,erictune/erictune.github.io,erictune/erictune.github.io,ronaldpetty/kubernetes.github.io,AlainRoy/alainroy.github.io,erictune/erictune.github.io,rata/kubernetes.github.io,aidevops/kubernetes.github.io,aidevops/kubernetes.github.io,ronaldpetty/kubernetes.github.io