build(deps-dev): Bump terser-webpack-plugin in /frontend (#512)

Bumps [terser-webpack-plugin](https://github.com/webpack-contrib/terser-webpack-plugin) from 2.3.6 to 3.0.0.
- [Release notes](https://github.com/webpack-contrib/terser-webpack-plugin/releases)
- [Changelog](https://github.com/webpack-contrib/terser-webpack-plugin/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/terser-webpack-plugin@v2.3.6...v3.0.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

frontend/package.json

@@ -44,7 +44,7 @@
     "prettier": "1.19.1",
     "sass-loader": "^8.0.0",
     "standard": "^14.1.0",
-    "terser-webpack-plugin": "^2.0.1",
+    "terser-webpack-plugin": "^3.0.0",
     "webpack": "^4.40.2",
     "webpack-cli": "^3.3.6",
     "webpack-dev-server": "^3.7.2",