fix: bump @slack/bolt from 3.22.0 to 4.2.1

Bumps [@slack/bolt](https://github.com/slackapi/bolt-js) from 3.22.0 to 4.2.1.
- [Release notes](https://github.com/slackapi/bolt-js/releases)
- [Commits](https://github.com/slackapi/bolt-js/compare/@slack/bolt@3.22.0...@slack/bolt@4.2.1)

---
updated-dependencies:
- dependency-name: "@slack/bolt"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]