Bump stylelint from 16.17.0 to 16.18.0

Bumps [stylelint](https://github.com/stylelint/stylelint) from 16.17.0 to 16.18.0.
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/main/CHANGELOG.md)
- [Commits](stylelint/stylelint@16.17.0...16.18.0)

---
updated-dependencies:
- dependency-name: stylelint
  dependency-version: 16.18.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -48,7 +48,7 @@
   },
   "dependencies": {
     "jsdom": "26.0.0",
-    "stylelint": "16.17.0",
+    "stylelint": "16.18.0",
     "@sitespeed.io/log": "0.2.6",
     "@sitespeed.io/plugin": "1.0.0"
   },