Bump postcss from 8.5.5 to 8.5.6 (#214)

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.5 to 8.5.6.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.5...8.5.6)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

package.json

@@ -18,7 +18,7 @@
     "https-proxy-agent": "^5.0.1",
     "next": "^15.1.0",
     "next-auth": "^5.0.0-beta.25",
-    "postcss": "8.5.5",
+    "postcss": "8.5.6",
     "react": "18.3.1",
     "react-dom": "18.3.1",
     "tailwindcss": "3.4.16",