Bump node-sass from 4.13.0 to 7.0.0

Bumps [node-sass](https://github.com/sass/node-sass) from 4.13.0 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@v4.13.0...v7.0.0)

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

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

Author: dependabot[bot]

package.json

@@ -88,7 +88,7 @@
     "eslint-plugin-jsx-a11y": "^6.2.3",
     "eslint-plugin-react": "^7.16.0",
     "mini-css-extract-plugin": "0.9.0",
-    "node-sass": "^4.13.0",
+    "node-sass": "^7.0.0",
     "prettier": "^1.13.5",
     "redux-logger": "^3.0.6",
     "sass-loader": "^8.0.0",