Bump mini-css-extract-plugin from 0.8.0 to 0.9.0 (#66)

Bumps [mini-css-extract-plugin](https://github.com/webpack-contrib/mini-css-extract-plugin) from 0.8.0 to 0.9.0.
- [Release notes](https://github.com/webpack-contrib/mini-css-extract-plugin/releases)
- [Changelog](https://github.com/webpack-contrib/mini-css-extract-plugin/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/mini-css-extract-plugin/compare/v0.8.0...v0.9.0)

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

package.json

@@ -55,7 +55,7 @@
     "file-loader": "^5.0.2",
     "html-webpack-plugin": "^3.2.0",
     "jest": "^24.1.0",
-    "mini-css-extract-plugin": "^0.8.0",
+    "mini-css-extract-plugin": "^0.9.0",
     "node-sass": "^4.13.0",
     "prettier": "^1.19.1",
     "sass-loader": "^8.0.0",