Bump node-sass from 6.0.0 to 7.0.0 in /core/examples/luigi-example-vu…

…e -> change node-sass to sass because of node-sass deprecation (SAP#2533)

* Bump node-sass from 6.0.0 to 7.0.0 in /core/examples/luigi-example-vue

Bumps [node-sass](https://github.com/sass/node-sass) from 6.0.0 to 7.0.0.
- [Release notes](https://github.com/sass/node-sass/releases)
- [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md)
- [Commits](sass/node-sass@v6.0.0...v7.0.0)

---
updated-dependencies:
- dependency-name: node-sass
  dependency-type: direct:development
...

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

* Change deprecated node-sass to sass

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Wiktor Doberschuetz <[email protected]>