npm: bump postcss in /web/themes/custom/contribtracker

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.49 to 8.5.3.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.49...8.5.3)

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

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

Author: dependabot[bot]

web/themes/custom/contribtracker/package-lock.json

@@ -43,7 +43,7 @@
     "gulp-sass-glob": "^1.1.0",
     "gulp-svgstore": "^9.0.0",
     "gulp-typescript": "^6.0.0-alpha.1",
-    "postcss": "^8.4.40",
+    "postcss": "^8.5.3",
     "postcss-scss": "^4.0.9",
     "prettier": "^3.4.1",
     "sass": "^1.81.0",