Bump webpack-cli from 3.3.7 to 3.3.8 in /js

Bumps [webpack-cli](https://github.com/webpack/webpack-cli) from 3.3.7 to 3.3.8.
- [Release notes](https://github.com/webpack/webpack-cli/releases)
- [Changelog](https://github.com/webpack/webpack-cli/blob/v3.3.8/CHANGELOG.md)
- [Commits](https://github.com/webpack/webpack-cli/compare/v3.3.7...v3.3.8)

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

js/package.json

@@ -41,7 +41,7 @@
     "vue-style-loader": "^4.1.2",
     "vue-template-compiler": "^2.6.10",
     "webpack": "^4.39.3",
-    "webpack-cli": "^3.3.7",
+    "webpack-cli": "^3.3.8",
     "webpack-merge": "^4.2.2"
   },
   "scripts": {