Bump slack-ruby-client from 0.12.0 to 0.13.0
Bump slack-ruby-client from 0.12.0 to 0.13.0

Bumps [slack-ruby-client](https://github.com/slack-ruby/slack-ruby-client) from 0.12.0 to 0.13.0.
- [Release notes](https://github.com/slack-ruby/slack-ruby-client/releases)
- [Changelog](https://github.com/slack-ruby/slack-ruby-client/blob/master/CHANGELOG.md)
- [Commits](https://github.com/slack-ruby/slack-ruby-client/compare/v0.12.0...v0.13.0)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
codeforamerica/michigan-benefits,codeforamerica/michigan-benefits,codeforamerica/michigan-benefits,codeforamerica/michigan-benefits