Bump engine.io from 6.1.0 to 6.1.3 in /playground

Bumps [engine.io](https://github.com/socketio/engine.io) from 6.1.0 to 6.1.3.
- [Release notes](https://github.com/socketio/engine.io/releases)
- [Changelog](https://github.com/socketio/engine.io/blob/main/CHANGELOG.md)
- [Commits](socketio/engine.io@6.1.0...6.1.3)

---
updated-dependencies:
- dependency-name: engine.io
  dependency-type: indirect
...

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

Author: dependabot[bot]