build(deps-dev): bump postcss from 8.5.3 to 8.5.4 in /frontend

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.3 to 8.5.4.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.3...8.5.4)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.4
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

frontend/package-lock.json

@@ -69,7 +69,7 @@
     "knip": "^5.59.1",
     "msw": "^2.8.7",
     "msw-storybook-addon": "^2.0.4",
-    "postcss": "^8.5.3",
+    "postcss": "^8.5.4",
     "postcss-import": "^16.1.0",
     "postcss-nesting": "^13.0.1",
     "rimraf": "^6.0.1",