chore(deps): update dependency postcss to v8.5.15

Author: renovate[bot]

package-lock.json

@@ -116,7 +116,7 @@
     "lodash.omit": "4.18.0",
     "lodash.omitby": "4.6.0",
     "lucide-react": "1.21.0",
-    "postcss": "8.5.14",
+    "postcss": "8.5.15",
     "react-day-picker": "8.10.2",
     "react-flagpack": "2.0.6",
     "react-hook-form": "7.73.1",