Bump postcss-cli from 9.1.0 to 11.0.0 in /docs

Bumps [postcss-cli](https://github.com/postcss/postcss-cli) from 9.1.0 to 11.0.0.
- [Release notes](https://github.com/postcss/postcss-cli/releases)
- [Changelog](https://github.com/postcss/postcss-cli/blob/master/CHANGELOG.md)
- [Commits](postcss/postcss-cli@9.1.0...11.0.0)

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

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

docs/package.json

@@ -22,6 +22,6 @@
   "devDependencies": {
     "autoprefixer": "^10.4.0",
     "postcss": "^8.3.7",
-    "postcss-cli": "^9.0.2"
+    "postcss-cli": "^11.0.0"
   }
 }