Bump stylelint and stylelint-config-sass-guidelines

Bumps [stylelint](https://github.com/stylelint/stylelint) and [stylelint-config-sass-guidelines](https://github.com/bjankord/stylelint-config-sass-guidelines). These dependencies needed to be updated together.

Updates `stylelint` from 12.0.1 to 13.0.0
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/stylelint/stylelint/compare/12.0.1...13.0.0)

Updates `stylelint-config-sass-guidelines` from 6.2.0 to 7.0.0
- [Release notes](https://github.com/bjankord/stylelint-config-sass-guidelines/releases)
- [Changelog](https://github.com/bjankord/stylelint-config-sass-guidelines/blob/master/CHANGELOG.md)
- [Commits](https://github.com/bjankord/stylelint-config-sass-guidelines/compare/v6.2.0...v7.0.0)

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

package.json

@@ -51,8 +51,8 @@
     "postcss-cli": "^7.1.0",
     "postcss-reporter": "^6.0.1",
     "rimraf": "^3.0.1",
-    "stylelint": "~12.0.1",
+    "stylelint": "~13.0.0",
-    "stylelint-config-sass-guidelines": "~6.2.0",
+    "stylelint-config-sass-guidelines": "~7.0.0",
     "stylelint-scss": "~3.14.2"
   },
   "engines": {