Bump json5 and grunt-babel in /assets/plugins/stickyfill

Bumps [json5](https://github.com/json5/json5) to 2.2.2 and updates ancestor dependency [grunt-babel](https://github.com/babel/grunt-babel). These dependencies need to be updated together.


Updates `json5` from 0.5.1 to 2.2.2
- [Release notes](https://github.com/json5/json5/releases)
- [Changelog](https://github.com/json5/json5/blob/main/CHANGELOG.md)
- [Commits](json5/json5@v0.5.1...v2.2.2)

Updates `grunt-babel` from 6.0.0 to 8.0.0
- [Release notes](https://github.com/babel/grunt-babel/releases)
- [Commits](babel/grunt-babel@v6.0.0...v8.0.0)

---
updated-dependencies:
- dependency-name: json5
  dependency-type: indirect
- dependency-name: grunt-babel
  dependency-type: direct:development
...

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

Author: dependabot[bot]

assets/plugins/stickyfill/package-lock.json

@@ -21,7 +21,7 @@
   "devDependencies": {
     "babel-preset-es2015": "^6.22.0",
     "grunt": "^1.0.1",
-    "grunt-babel": "^6.0.0",
+    "grunt-babel": "^8.0.0",
     "grunt-bump": "^0.8.0",
     "grunt-contrib-uglify": "^2.0.0",
     "grunt-contrib-watch": "^1.0.0",