Bump karma from 3.1.4 to 4.0.0 in /js

Bumps [karma](https://github.com/karma-runner/karma) from 3.1.4 to 4.0.0.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](https://github.com/karma-runner/karma/compare/v3.1.4...v4.0.0)

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

js/package.json

@@ -27,7 +27,7 @@
     "@babel/preset-env": "^7.2.3",
     "babel-loader": "^8.0.5",
     "css-loader": "^2.1.0",
-    "karma": "^3.1.4",
+    "karma": "^4.0.0",
     "mini-css-extract-plugin": "^0.5.0",
     "uglifyjs-webpack-plugin": "^2.1.1",
     "webpack": "^4.28.4",