Bump node-sass from 4.14.1 to 7.0.0 in /client

Bumps [node-sass](https://github.com/sass/node-sass) from 4.14.1 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@v4.14.1...v7.0.0)

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

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

Author: dependabot[bot]

client/package.json

@@ -16,7 +16,7 @@
     "js-cookie": "~2.2.1",
     "lodash": "~4.17.15",
     "loglevel": "~1.6.8",
-    "node-sass": "~4.14.1",
+    "node-sass": "~7.0.0",
     "path": "~0.12.7",
     "prop-types": "~15.7.2",
     "react": "~16.13.0",