Allow setting namespace in `helm template` without a kubeconfig

If you don't have a working kubeconfig, `helm template` does not respect
the `--namespace` option. It gets set on the settings object, but does
not get returned. `helm template` should not require a working
kubeconfig or any communication with a kubernetes cluster.

Signed-off-by: Alex Hunt <alex.hunt@materialize.com>

pkg/cli/environment.go

@@ -223,6 +223,9 @@ func (s *EnvSettings) Namespace() string {
 	if ns, _, err := s.config.ToRawKubeConfigLoader().Namespace(); err == nil {
 		return ns
 	}
+	if s.namespace != "" {
+		return s.namespace
+	}
 	return "default"
 }