Use yaml instead of json for policy file

Because usage of json for policy file will be deprecated and replaced
by yaml[1].

[1] https://governance.openstack.org/tc/goals/selected/wallaby/migrate-policy-format-from-json-to-yaml.html

Depends-on: https://review.opendev.org/769647
Change-Id: I296a34f14cb3cd88ac8a969d224ab7e55b79b137

manifests/policy.pp

@@ -20,12 +20,12 @@
 #   Defaults to empty hash.
 #
 # [*policy_path*]
-#   (Optional) Path to the nova policy.json file
-#   Defaults to /etc/placement/policy.json
+#   (Optional) Path to the nova policy.yaml file
+#   Defaults to /etc/placement/policy.yaml
 #
 class placement::policy (
   $policies    = {},
-  $policy_path = '/etc/placement/policy.json',
+  $policy_path = '/etc/placement/policy.yaml',
 ) {
 
   include placement::deps
@@ -34,9 +34,10 @@ class placement::policy (
   validate_legacy(Hash, 'validate_hash', $policies)
 
   Openstacklib::Policy::Base {
-    file_path  => $policy_path,
-    file_user  => 'root',
-    file_group => $::placement::params::group,
+    file_path   => $policy_path,
+    file_user   => 'root',
+    file_group  => $::placement::params::group,
+    file_format => 'yaml',
   }
 
   create_resources('openstacklib::policy::base', $policies)

releasenotes/notes/migrate-policy-format-from-json-to-yaml-3ad4426817969de5.yaml

@@ -0,0 +1,4 @@
+---
+upgrade:
+  - |
+    Now policy.yaml is used by default instead of policy.json.

spec/classes/placement_policy_spec.rb

@@ -4,7 +4,7 @@ describe 'placement::policy' do
   shared_examples 'placement::policy' do
     let :params do
       {
-        :policy_path => '/etc/placement/policy.json',
+        :policy_path => '/etc/placement/policy.yaml',
         :policies    => {
           'context_is_admin' => {
             'key'   => 'context_is_admin',
@@ -14,12 +14,18 @@ describe 'placement::policy' do
       }
     end
 
-    it { is_expected.to contain_openstacklib__policy__base('context_is_admin').with(
-      :key        => 'context_is_admin',
-      :value      => 'foo:bar',
-      :file_user  => 'root',
-      :file_group => 'placement',
-    )}
+    it 'set up the policies' do
+      is_expected.to contain_openstacklib__policy__base('context_is_admin').with(
+        :key         => 'context_is_admin',
+        :value       => 'foo:bar',
+        :file_user   => 'root',
+        :file_group  => 'placement',
+        :file_format => 'yaml',
+      )
+      is_expected.to contain_oslo__policy('placement_config').with(
+        :policy_file => '/etc/placement/policy.yaml',
+      )
+    end
   end
 
   on_supported_os({