Bump sass from 1.28.0 to 1.29.0

Bumps [sass](https://github.com/sass/dart-sass) from 1.28.0 to 1.29.0.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/master/CHANGELOG.md)
- [Commits](sass/dart-sass@1.28.0...1.29.0)

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

Author: dependabot[bot]

package.json

@@ -44,7 +44,7 @@
     "grunt-sass": "3.1.0",
     "grunt-stylelint": "0.15.0",
     "load-grunt-tasks": "5.1.0",
-    "sass": "1.28.0",
+    "sass": "1.29.0",
     "stylelint": "13.7.2",
     "stylelint-order": "4.1.0",
     "stylelint-scss": "3.18.0"