Bump webpack-cli from 3.0.3 to 3.0.8 in /js

Bumps [webpack-cli](https://github.com/webpack/webpack-cli) from 3.0.3 to 3.0.8.
- [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/v3.0.3...v3.0.8)

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

js/package.json

@@ -25,7 +25,7 @@
     "mini-css-extract-plugin": "^0.4.0",
     "node-sass": "^4.5.3",
     "webpack": "^4.12.0",
-    "webpack-cli": "^3.0.3",
+    "webpack-cli": "^3.0.8",
     "webpack-merge": "^4.1.2",
     "karma": "^2.0.2"
   },