Switch to namespace sdtlib functions

puppetlabs-stdlib deprecated the existing functions in favor of
the new stdlib:: functions in 9.0.0. The version was released a few
years ago and now we assume we are ready to adopt to the migration.

Change-Id: If275592289ceccdebc2494007ae891be0585e7da
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

manifests/capi_helm.pp

@@ -149,7 +149,7 @@ class magnum::capi_helm (
       owner   => $kubeconfig_owner,
       group   => $kubeconfig_group,
       mode    => $kubeconfig_mode,
-      content => to_yaml($kubeconfig),
+      content => stdlib::to_yaml($kubeconfig),
       require => Anchor['magnum::config::begin'],
       before  => Anchor['magnum::config::end'],
     }

metadata.json

@@ -7,7 +7,7 @@
         },
         {
             "name": "puppetlabs/stdlib",
-            "version_requirement": ">=5.0.0 <10.0.0"
+            "version_requirement": ">=9.0.0 <10.0.0"
         },
         {
             "name": "openstack/keystone",