Bump node-sass from 4.12.0 to 7.0.0

Bumps [node-sass](https://github.com/sass/node-sass) from 4.12.0 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](https://github.com/sass/node-sass/compare/v4.12.0...v7.0.0)

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

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

package.json

@@ -25,7 +25,7 @@
     "markdown-it-mark": "2.0.0",
     "markdown-it-smartarrows": "1.0.1",
     "morgan": "1.9.1",
-    "node-sass": "4.12.0",
+    "node-sass": "7.0.0",
     "pg": "7.11.0",
     "pug": "2.0.3",
     "socket.io": "^2.2.0",