build(deps): bump node-sass from 4.12.0 to 4.13.1 Bumps [node-sass](https://github.com/sass/node-sass) from 4.12.0 to 4.13.1. - [Release notes](https://github.com/sass/node-sass/releases) - [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md) - [Commits](https://github.com/sass/node-sass/compare/v4.12.0...v4.13.1) Signed-off-by: dependabot[bot]