Update dependency stylelint to v16.21.0

Author: renovate[bot]

package-lock.json

@@ -61,7 +61,7 @@
         "postcss-simple-vars": "7.0.1",
         "postcss-sort-media-queries": "5.2.0",
         "prettier": "3.4.2",
-        "stylelint": "16.20.0",
+        "stylelint": "16.21.0",
         "stylelint-config-recommended": "15.0.0",
         "stylelint-config-standard": "37.0.0",
         "ts-loader": "9.5.2",