[FEATURE] add kubectl

[davidkarlsen]

Is your feature request related to a problem? Please describe.

Can you add support for kubectl too? Some tools rely on kubectl.

Describe the solution you'd like

Add install and cache for kubectl

Describe alternatives you've considered

azure/setup-kubectl

Additional context

[tetchel]

There are no kubectl binaries on GitHub so this is out of scope of this action.

However when installing oc, kubectl is also installed (it is included in the tar file and extracted just the same).

But then you get whichever kubectl/k8s version that version of oc/ocp corresponds to, rather than being able to pick a kubectl/k8s version.