chore(deps-dev): bump postcss from 8.5.10 to 8.5.14 in /frontend

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.10 to 8.5.14.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.10...8.5.14)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.14
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

frontend/package.json

@@ -69,7 +69,7 @@
     "jsonc-eslint-parser": "^2.1.0",
     "ng-packagr": "~19.2.0",
     "nx": "20.5.0",
-    "postcss": "^8.4.5",
+    "postcss": "^8.5.14",
     "postcss-url": "~10.1.3",
     "prettier": "^2.6.2",
     "topojson-client": "^3.1.0",