Bump css-loader from 6.8.1 to 7.0.0

Bumps [css-loader](https://github.com/webpack-contrib/css-loader) from 6.8.1 to 7.0.0.
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/css-loader@v6.8.1...v7.0.0)

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

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

package.json

@@ -68,7 +68,7 @@
     "coffee-react": "~5.0.1",
     "coffeescript": "~2.7.0",
     "copy-webpack-plugin": "~11.0.0",
-    "css-loader": "~6.8.1",
+    "css-loader": "~7.0.0",
     "ejs": "~3.1.9",
     "engine.io-client": "~6.5.3",
     "enzyme": "~3.11.0",