Bump slackapi/slack-github-action from 2.0.0 to 2.1.1

---
updated-dependencies:
- dependency-name: slackapi/slack-github-action
  dependency-version: 2.1.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/notify_slack.yml

@@ -9,7 +9,7 @@ jobs:
     timeout-minutes: 5
     if: github.event.discussion && github.event.comment
     steps:
-      - uses: slackapi/slack-github-action@485a9d42d3a73031f12ec201c457e2162c45d02d # v2.0.0
+      - uses: slackapi/slack-github-action@91efab103c0de0a537f72a35f6b8cda0ee76bf0a # v2.1.1
         with:
           method: chat.postMessage
           payload: |