Update dependency postcss to v8.5.3 (#2259)

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

Author: renovate[bot]

package-lock.json

@@ -83,7 +83,7 @@
     "mini-css-extract-plugin": "1.6.2",
     "npm-run-all2": "5.0.2",
     "pleasantest": "3.1.0",
-    "postcss": "8.4.31",
+    "postcss": "8.5.3",
     "postcss-inline-svg": "4.1.0",
     "postcss-loader": "4.3.0",
     "postcss-media-minmax": "5.0.0",