Bump webpack-cli from 3.3.8 to 3.3.9

Bumps [webpack-cli](https://github.com/webpack/webpack-cli) from 3.3.8 to 3.3.9.
- [Release notes](https://github.com/webpack/webpack-cli/releases)
- [Changelog](https://github.com/webpack/webpack-cli/blob/v3.3.9/CHANGELOG.md)
- [Commits](https://github.com/webpack/webpack-cli/compare/v3.3.8...v3.3.9)

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

package.json

@@ -82,7 +82,7 @@
     "uglifyjs-3-webpack-plugin": "^1.2.4",
     "unfetch": "^3.0.0",
     "webpack": "^4.40.2",
-    "webpack-cli": "^3.3.8",
+    "webpack-cli": "^3.3.9",
     "webpack-manifest-plugin": "^2.0.4"
   },
   "engines": {