chore(dev-deps): update dependency postcss to v8.4.31

Author: renovate[bot]

package-lock.json

@@ -79,7 +79,7 @@
     "karma-jasmine": "4.0.2",
     "karma-webpack": "4.0.2",
     "npm-run-all": "4.1.5",
-    "postcss": "8.4.24",
+    "postcss": "8.4.31",
     "postcss-banner": "4.0.1",
     "postcss-cli": "9.1.0",
     "prettier": "2.8.8",