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>

Author: dependabot[bot]

package.json

@@ -186,7 +186,7 @@
     "json-loader": "^0.5.7",
     "mini-css-extract-plugin": "^0.5.0",
     "modernizr-webpack-plugin": "^1.0.7",
-    "node-sass": "^4.13.1",
+    "node-sass": "^7.0.0",
     "nodemon": "^1.18.10",
     "optimize-css-assets-webpack-plugin": "^5.0.1",
     "progress-bar-webpack-plugin": "^1.12.1",