Bump ws from 6.1.2 to 6.2.2 in /reveal.js-3.9.2

Bumps [ws](https://github.com/websockets/ws) from 6.1.2 to 6.2.2.
- [Release notes](https://github.com/websockets/ws/releases)
- [Commits](websockets/ws@6.1.2...6.2.2)

---
updated-dependencies:
- dependency-name: ws
  dependency-type: indirect
...

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