Bump webpack-cli from 3.3.12 to 4.0.0

Bumps [webpack-cli](https://github.com/webpack/webpack-cli) from 3.3.12 to 4.0.0.
- [Release notes](https://github.com/webpack/webpack-cli/releases)
- [Changelog](https://github.com/webpack/webpack-cli/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack/webpack-cli/compare/v3.3.12...webpack-cli@4.0.0)

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

package.json

@@ -103,7 +103,7 @@
     "url-polyfill": "^1.1.5",
     "walk": "^2.3.9",
     "webpack": "4.44.2",
-    "webpack-cli": "^3.3.2",
+    "webpack-cli": "^4.0.0",
     "webpack-dev-middleware": "^3.6.2",
     "webpack-dev-server": "^3.3.1",
     "worker-loader": "^3.0.0",