chore(deps): update dependency postcss to v8.5.15 (#276)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -43,7 +43,7 @@
     "mini-css-extract-plugin": "2.10.2",
     "node-fetch": "3.3.2",
     "npm-run-all2": "9.0.0",
-    "postcss": "8.5.14",
+    "postcss": "8.5.15",
     "postcss-loader": "8.2.1",
     "postcss-preset-env": "11.3.0",
     "sass": "1.99.0",