codefresh_api_key token property is not currently set as sensitive

[simonbronner]

See: https://github.com/codefresh-io/terraform-provider-codefresh/blob/master/codefresh/resource_api_key.go#L32

[sandrogattuso]

@palson-cf @kosta709 I believe this was addressed by #16

[korenyoni]

@palson-cf @kosta709 I believe this was addressed by #16

Correct