Fix npm build issue related to mini-css-extract-plugin

Applied workaround that's described in webpack-contrib/mini-css-extract-plugin#896.

Author: peterkeating

content/package.json

@@ -29,7 +29,7 @@
         "imagemin-optipng": "^8.0.0",
         "imagemin-pngquant": "^9.0.1",
         "imagemin-svgo": "^9.0.0",
-        "mini-css-extract-plugin": "^2.2.2",
+        "mini-css-extract-plugin": "~2.4.5",
         "npm-run-all": "^4.1.5",
         "postcss": "^8.3.6",
         "postcss-loader": "^6.1.1",