Bump stylelint from 13.7.2 to 13.8.0

Bumps [stylelint](https://github.com/stylelint/stylelint) from 13.7.2 to 13.8.0.
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/master/CHANGELOG.md)
- [Commits](stylelint/stylelint@13.7.2...13.8.0)

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

Author: dependabot[bot]

package.json

@@ -27,7 +27,7 @@
     "grunt-stylelint": "0.15.0",
     "load-grunt-tasks": "5.1.0",
     "sass": "1.29.0",
-    "stylelint": "13.7.2",
+    "stylelint": "13.8.0",
     "stylelint-order": "4.1.0",
     "stylelint-scss": "3.18.0"
   },