Update dependency postcss to v8.4.12

Author: renovate-bot

package.json

@@ -74,7 +74,7 @@
     "jest": "27.5.1",
     "lint-staged": "12.3.6",
     "lodash-es": "4.17.21",
-    "postcss": "8.4.11",
+    "postcss": "8.4.12",
     "prettier": "2.6.0",
     "react": "17.0.2",
     "react-dom": "17.0.2",