chore: bump stylelint from 15.5.0 to 15.6.0

Bumps [stylelint](https://github.com/stylelint/stylelint) from 15.5.0 to 15.6.0.
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/main/CHANGELOG.md)
- [Commits](stylelint/stylelint@15.5.0...15.6.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -46,7 +46,7 @@
     "nyc": "^15.1.0",
     "sinon": "^15.0.4",
     "sinon-chrome": "^3.0.1",
-    "stylelint": "^15.5.0",
+    "stylelint": "^15.6.0",
     "stylelint-config-standard": "^33.0.0",
     "stylelint-no-unsupported-browser-features": "^6.1.0",
     "web-ext": "^7.6.1"