Bump socket.io-parser and karma

Bumps [socket.io-parser](https://github.com/socketio/socket.io-parser) to 4.2.1 and updates ancestor dependency [karma](https://github.com/karma-runner/karma). These dependencies need to be updated together.


Updates `socket.io-parser` from 3.1.3 to 4.2.1
- [Release notes](https://github.com/socketio/socket.io-parser/releases)
- [Changelog](https://github.com/socketio/socket.io-parser/blob/main/CHANGELOG.md)
- [Commits](socketio/socket.io-parser@3.1.3...4.2.1)

Updates `karma` from 2.0.3 to 6.4.1
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v2.0.3...v6.4.1)

---
updated-dependencies:
- dependency-name: socket.io-parser
  dependency-type: indirect
- dependency-name: karma
  dependency-type: direct:development
...

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Author: dependabot[bot]