build(deps-dev): bump mini-css-extract-plugin in /frontend (#628)

Bumps [mini-css-extract-plugin](https://github.com/webpack-contrib/mini-css-extract-plugin) from 0.11.3 to 1.0.0.
- [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](webpack/mini-css-extract-plugin@v0.11.3...v1.0.0)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

frontend/package.json

@@ -38,7 +38,7 @@
     "eslint-plugin-prettier": "^3.1.0",
     "file-loader": "^6.0.0",
     "html-webpack-plugin": "^4.0.1",
-    "mini-css-extract-plugin": "^0.11.0",
+    "mini-css-extract-plugin": "^1.0.0",
     "node-sass": "^4.12.0",
     "optimize-css-assets-webpack-plugin": "^5.0.3",
     "prettier": "1.19.1",