Bump node-sass from 5.0.0 to 7.0.0 in /src

Bumps [node-sass](https://github.com/sass/node-sass) from 5.0.0 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@v5.0.0...v7.0.0)

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

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

src/package.json

@@ -7,7 +7,7 @@
   "author": "Neoground GmbH",
   "license": "MIT",
   "dependencies": {
-    "node-sass": "^5.0.0"
+    "node-sass": "^7.0.0"
   },
   "scripts": {
     "build-css": "node-sass --include-path scss scss/style.scss css/style.css",