chore(deps): bump slackapi/slack-github-action from 1.26.0 to 2.1.1

Bumps [slackapi/slack-github-action](https://github.com/slackapi/slack-github-action) from 1.26.0 to 2.1.1.
- [Release notes](https://github.com/slackapi/slack-github-action/releases)
- [Commits](slackapi/slack-github-action@70cd7be...91efab1)

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

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

Author: dependabot[bot]

.github/workflows/check_for_broken_links.yml

@@ -42,7 +42,7 @@ jobs:
       - name: Send custom JSON data to Slack workflow
         if: steps.checkLinks.outputs.result
         id: slack
-        uses: slackapi/slack-github-action@70cd7be8e40a46e8b0eced40b0de447bdb42f68e # v1.26.0
+        uses: slackapi/slack-github-action@91efab103c0de0a537f72a35f6b8cda0ee76bf0a # v2.1.1
         with:
           payload: |
             {