fix(deps): bump @slack/web-api from 6.12.0 to 6.12.1

Bumps [@slack/web-api](https://github.com/slackapi/node-slack-sdk) from 6.12.0 to 6.12.1.
- [Release notes](https://github.com/slackapi/node-slack-sdk/releases)
- [Commits](https://github.com/slackapi/node-slack-sdk/compare/@slack/[email protected]...@slack/[email protected])

---
updated-dependencies:
- dependency-name: "@slack/web-api"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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