Improve logging for the JIRA issue closing service

CHANGELOG-EE

+v 7.2.0
+  - Better logging for the JIRA issue closing service
+
 v 7.1.0
   - Synchronize LDAP-enabled GitLab administrators with an LDAP group (Marvin Frick, sponsored by SinnerSchrader)
   - Synchronize SSH keys with LDAP (Oleg Girko (Jolla) and Marvin Frick (SinnerSchrader))

app/models/project_services/jira_service.rb

@@ -74,9 +74,12 @@ class JiraService < Service
       }
     }
 
+    json_body = message.to_json
+    Rails.logger.info("#{self.class.name}: sending POST with body #{json_body} to #{url}")
+
     JiraService.post(
       url,
-      body: message.to_json,
+      body: json_body,
       headers: {
         'Content-Type' => 'application/json',
         'Authorization' => "Basic #{auth}"