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

@@ -38,7 +38,7 @@
     "vue-loader": "^15.9.3",
     "vue-template-compiler": "^2.6.12",
     "webpack": "^4.44.2",
-    "webpack-cli": "^3.3.12",
+    "webpack-cli": "^4.0.0",
     "webpack-merge": "^4.2.2",
     "webpack-node-externals": "^2.5.2"
   },