Update css-loader requirement to ^1.0.0

Updates the requirements on [css-loader](https://github.com/webpack-contrib/css-loader) to permit the latest version.
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/css-loader/commits/v1.0.0)

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

package.json

@@ -21,7 +21,7 @@
     "babel-polyfill": "^6.23.0",
     "babel-preset-es2015": "^6.24.0",
     "babel-preset-react": "^6.23.0",
-    "css-loader": "^0.28.11",
+    "css-loader": "^1.0.0",
     "extract-text-webpack-plugin": "^2.1.0",
     "file-loader": "^1.1.11",
     "flumpt": "^0.3.1",