Bump node-sass from 4.13.1 to 7.0.0

Bumps [node-sass](https://github.com/sass/node-sass) from 4.13.1 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@v4.13.1...v7.0.0)

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

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

package.json

@@ -28,7 +28,7 @@
     "mini-css-extract-plugin": "^0.5.0",
     "mocha": "^5.2.0",
     "mochawesome": "^4.1.0",
-    "node-sass": "^4.13.0",
+    "node-sass": "^7.0.0",
     "postcss-loader": "^3.0.0",
     "postcss-preset-env": "^6.5.0",
     "sass-loader": "^8.0.0",