Bump engine.io from 3.6.0 to 3.6.1 in /slides

Bumps [engine.io](https://github.com/socketio/engine.io) from 3.6.0 to 3.6.1.
- [Release notes](https://github.com/socketio/engine.io/releases)
- [Changelog](https://github.com/socketio/engine.io/blob/main/CHANGELOG.md)
- [Commits](socketio/engine.io@3.6.0...3.6.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]