Update dependency postcss to v8.4.26

Author: renovate[bot]

package-lock.json

@@ -31,7 +31,7 @@
     "axios": "0.27.2",
     "nanoid": "4.0.0",
     "next": "12.2.5",
-    "postcss": "8.4.16",
+    "postcss": "8.4.26",
     "react": "18.2.0",
     "react-dom": "18.2.0",
     "tailwindcss": "3.1.8"