Bump i18n-js from 3.9.2 to 4.0.0

Bumps [i18n-js](https://github.com/fnando/i18n-js) from 3.9.2 to 4.0.0.
- [Release notes](https://github.com/fnando/i18n-js/releases)
- [Changelog](https://github.com/fnando/i18n-js/blob/main/CHANGELOG.md)
- [Commits](https://github.com/fnando/i18n-js/compare/v3.9.2...v4.0.0)

---
updated-dependencies:
- dependency-name: i18n-js
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

app/assets/javascripts/application.js

@@ -14,8 +14,6 @@
 //= require pagedown_bootstrap
 //= require rails-timeago
 //= require locales/jquery.timeago.de.js
-//= require i18n
-//= require i18n/translations
 //
 // lib/assets
 //= require flash