chore(deps): bump the slack api version to 2.2.0

[zimeg]

Summary

This PR bumps the API version to deno_slack_api@2.2.0 to reflect the latest release.

Testing

$ deno task test  # Passes

Requirements

• [x] I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• [x] I've read and agree to the Code of Conduct.
• [x] I've ran deno task test after making the changes.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (4791d00) 98.07% compared to head (0ba1dbd) 98.15%. Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #277 +/- ## ========================================== + Coverage 98.07% 98.15% +0.08% ========================================== Files 58 58 Lines 2280 2280 Branches 137 147 +10 ========================================== + Hits 2236 2238 +2 Misses 42 42 + Partials 2 0 -2 ```

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[srajiang]

I approve this message! thanks @zimeg