Update dependency stylelint to v16.20.0

| datasource | package   | from    | to      |
| ---------- | --------- | ------- | ------- |
| npm        | stylelint | 16.19.1 | 16.20.0 |


## [v16.20.0](https://github.com/stylelint/stylelint/blob/HEAD/CHANGELOG.md#16200---2025-05-29)

It fixes 2 bugs with the built-in rules.

-   Fixed: `function-url-no-scheme-relative` false negatives for `@import` ([#8576](stylelint/stylelint#8576)) ([@pamelalozano16](https://github.com/pamelalozano16)).
-   Fixed: `shorthand-property-no-redundant-values` false negatives for additional radius ([#8539](stylelint/stylelint#8539)) ([@ryo-manba](https://github.com/ryo-manba)).

Author: renovate[bot]

package.json

@@ -51,7 +51,7 @@
     "react": "17.0.2",
     "react-dom": "17.0.2",
     "strong-mock": "~8.0.1",
-    "stylelint": "16.19.1",
+    "stylelint": "16.20.0",
     "stylelint-config-recommended": "16.0.0",
     "stylelint-config-styled-components": "0.1.1",
     "stylelint-processor-styled-components": "1.10.0",