Update dependency postcss to v8.4.31

Author: renovate[bot]

package-lock.json

@@ -28,7 +28,7 @@
         "jsdom": "22.1.0",
         "laravel-mix": "6.0.49",
         "lodash": "4.17.21",
-        "postcss": "8.4.29",
+        "postcss": "8.4.31",
         "prettier": "3.0.3",
         "tailwindcss": "3.3.3",
         "vue-loader": "17.2.2"