[Dependencies]: Bump sass-loader from 14.2.1 to 15.0.0

Bumps [sass-loader](https://github.com/webpack-contrib/sass-loader) from 14.2.1 to 15.0.0.
- [Release notes](https://github.com/webpack-contrib/sass-loader/releases)
- [Changelog](https://github.com/webpack-contrib/sass-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/sass-loader@v14.2.1...v15.0.0)

---
updated-dependencies:
- dependency-name: sass-loader
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -19,7 +19,7 @@
     "mini-css-extract-plugin": "^1.6.2",
     "robotstxt-webpack-plugin": "^7.0.0",
     "sass": "^1.43.4",
-    "sass-loader": "^14.1.0",
+    "sass-loader": "^15.0.0",
     "style-loader": "^2.0.0",
     "url-loader": "^4.1.1",
     "webpack": "^4.46.0",