⬆️ Bump css-loader from 6.8.1 to 6.9.0 in /shifter

Bumps [css-loader](https://github.com/webpack-contrib/css-loader) from 6.8.1 to 6.9.0.
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/css-loader@v6.8.1...v6.9.0)

---
updated-dependencies:
- dependency-name: css-loader
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

shifter/package.json

@@ -19,7 +19,7 @@
   },
   "homepage": "https://github.com/TobySuch/Shifter#readme",
   "devDependencies": {
-    "css-loader": "^6.8.1",
+    "css-loader": "^6.9.0",
     "source-map-loader": "^4.0.2",
     "style-loader": "^3.3.3",
     "tailwindcss": "^3.4.1",