Bump postcss from 8.3.9 to 8.3.11

Bumps [postcss](https://github.com/postcss/postcss) from 8.3.9 to 8.3.11.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.3.9...8.3.11)

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

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

package.json

@@ -25,7 +25,7 @@
   "devDependencies": {
     "autoprefixer": "^10.3.7",
     "eslint-plugin-compat": "^4.0.0",
-    "postcss": "^8.3.9",
+    "postcss": "^8.3.11",
     "postcss-cli": "^9.0.2",
     "prettier": "2.4.1",
     "xo": "^0.46.4"