chore: Bump "postcss" package version to 8.5.9

Made with ❤️️ by updatecli

Author: updateclibot[bot]

package-lock.json

@@ -59,7 +59,7 @@
     "lazysizes": "^5.3.2",
     "markdownlint-cli2": "^0.10.0",
     "netlify-plugin-submit-sitemap": "^0.4.0",
-    "postcss": "^8.5.6",
+    "postcss": "^8.5.9",
     "postcss-cli": "^11.0.1",
     "purgecss-whitelister": "^2.4.0",
     "shx": "^0.4.0",