Bump node-sass from 4.9.2 to 7.0.0 in /reactjs

Bumps [node-sass](https://github.com/sass/node-sass) from 4.9.2 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@v4.9.2...v7.0.0)

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

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

Author: dependabot[bot]

reactjs/package.json

@@ -12,7 +12,7 @@
     "next-redux-saga": "^3.0.0-beta.1",
     "next-redux-wrapper": "^2.0.0",
     "next-routes": "^1.4.2",
-    "node-sass": "^4.9.2",
+    "node-sass": "^7.0.0",
     "node-sass-glob-importer": "^5.2.0",
     "nprogress": "^0.2.0",
     "prop-types": "^15.6.2",