Bump postcss from 8.4.47 to 8.5.4 in /src/frontend (#1205)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.47 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@8.4.47...8.5.4)

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

Signed-off-by: dependabot[bot] <support@github.com>
Signed-off-by: polatengin <polatengin@users.noreply.github.com>
Co-authored-by: polatengin <polatengin@users.noreply.github.com>

Author: dependabot[bot]

src/frontend/package-lock.json

@@ -82,7 +82,7 @@
     "jest-junit": "16.0.0",
     "moment-locales-webpack-plugin": "1.2.0",
     "node-jq": "6.0.1",
-    "postcss": "8.4.47",
+    "postcss": "8.5.4",
     "process": "0.11.10",
     "rimraf": "6.0.1",
     "sass": "1.86.3",