chore(deps): bump redis from 3.1.2 to 4.2.0 in /images/socketio

Bumps [redis](https://github.com/redis/node-redis) from 3.1.2 to 4.2.0.
- [Release notes](https://github.com/redis/node-redis/releases)
- [Changelog](https://github.com/redis/node-redis/blob/master/CHANGELOG.md)
- [Commits](https://github.com/redis/node-redis/compare/v3.1.2...redis@4.2.0)

---
updated-dependencies:
- dependency-name: redis
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

images/socketio/package.json

@@ -6,7 +6,7 @@
   "license": "MIT",
   "dependencies": {
     "express": "^4.17.1",
-    "redis": "^3.1.1",
+    "redis": "^4.2.0",
     "socket.io": "^2.4.0",
     "superagent": "^5.1.0"
   }