build(deps-dev): bump mini-css-extract-plugin from 0.9.0 to 0.11.0

Bumps [mini-css-extract-plugin](https://github.com/webpack-contrib/mini-css-extract-plugin) from 0.9.0 to 0.11.0.
- [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-contrib/mini-css-extract-plugin@v0.9.0...v0.11.0)

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

packages/purgecss-webpack-plugin/package.json

@@ -47,7 +47,7 @@
     "@types/webpack": "^4.41.12",
     "@types/webpack-sources": "^1.4.0",
     "css-loader": "^4.0.0",
-    "mini-css-extract-plugin": "^0.9.0"
+    "mini-css-extract-plugin": "^0.11.0"
   },
   "peerDependencies": {
     "webpack": "*"