build(deps-dev): bump css-loader from 5.2.4 to 6.2.0 in /frontend (#1033)

Bumps [css-loader](https://github.com/webpack-contrib/css-loader) from 5.2.4 to 6.2.0.
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](webpack/css-loader@v5.2.4...v6.2.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

frontend/package-lock.json

@@ -26,7 +26,7 @@
     "babel-plugin-prismjs": "^2.0.0",
     "babel-polyfill": "^6.26.0",
     "clean-webpack-plugin": "^3.0.0",
-    "css-loader": "^5.2.4",
+    "css-loader": "^6.2.0",
     "css-minimizer-webpack-plugin": "^2.0.0",
     "eslint": "^7.26.0",
     "eslint-config-prettier": "^6.2.0",