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:production
...

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

Author: dependabot[bot]

package.json

@@ -12,7 +12,7 @@
     "dotenv": "^8.2.0",
     "isomorphic-unfetch": "^3.0.0",
     "next": "^9.3.2",
-    "node-sass": "4.13",
+    "node-sass": "7.0",
     "react": "^16.12.0",
     "react-dom": "^16.12.0",
     "react-ga": "^2.7.0",