linode-cli k8s-alpha create should prevalidate cluster names

[displague]

Using the label: k8s_test, for example, will result in a nearly completed cluster and a very late error.

module.k8s.linode_instance.k8s_master (remote-exec): name: Invalid value: "k8s_test-master-1": a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')

[asauber]

This has been on my personal to do list for a while. Thanks for codifying it

[displague]

Hyphens and dots are valid Linode instance names. This may no longer be a concern.

[LBGarber]

Closing this issue as k8s-alpha has been removed from linode-cli.