Bump babel-loader from 7.1.5 to 8.0.4 in /js

Bumps [babel-loader](https://github.com/babel/babel-loader) from 7.1.5 to 8.0.4.
- [Release notes](https://github.com/babel/babel-loader/releases)
- [Changelog](https://github.com/babel/babel-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel-loader/compare/v7.1.5...v8.0.4)

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

js/package.json

@@ -23,7 +23,7 @@
   },
   "devDependencies": {
     "babel-core": "^6.26.0",
-    "babel-loader": "^7.1.5",
+    "babel-loader": "^8.0.4",
     "babel-preset-env": "^1.7.0",
     "css-loader": "^1.0.0",
     "karma": "^3.0.0",