Merge branch 'jnnkl-eventlistener-release-show' into 'master'

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!53856

app/assets/javascripts/pages/projects/releases/show/index.js

 import initShowRelease from '~/releases/mount_show';
 
-document.addEventListener('DOMContentLoaded', initShowRelease);
+initShowRelease();