chore(deps): bump postcss from 8.5.15 to 8.5.18 (#5651)

Author: dependabot[bot]

package-lock.json

@@ -92,7 +92,7 @@
     "next-mdx-remote": "^6.0.0",
     "node-fetch": "^3.3.2",
     "node-fetch-2": "npm:node-fetch@^2.7.0",
-    "postcss": "^8.5.10",
+    "postcss": "^8.5.18",
     "prettier": "^3.3.3",
     "react": "^18",
     "react-dom": "^18",