Use nullcheck operator instead of checking for null

app/services/projects/update_service.rb

@@ -36,7 +36,7 @@ module Projects
     end
     def run_auto_devops_pipeline?
-      return false if project.repository.gitlab_ci_yml || project.auto_devops.nil? || !project.auto_devops.previous_changes.include?('enabled')
+      return false if project.repository.gitlab_ci_yml || !project.auto_devops&.previous_changes&.include?('enabled')
       project.auto_devops.enabled? || (project.auto_devops.enabled.nil? && Gitlab::CurrentSettings.auto_devops_enabled?)
     end