chore(deps): bump slackapi/slack-github-action

Bumps the notifications group with 1 update: [slackapi/slack-github-action](https://github.com/slackapi/slack-github-action).


Updates `slackapi/slack-github-action` from 1.24.0 to 2.1.1
- [Release notes](https://github.com/slackapi/slack-github-action/releases)
- [Commits](slackapi/slack-github-action@v1.24.0...v2.1.1)

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

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

Author: dependabot[bot]

.github/workflows/gptchangelog.yml

@@ -723,7 +723,7 @@ jobs:
     runs-on: blacksmith-4vcpu-ubuntu-2404
     steps:
       - name: Send Slack notification for sync PR
-        uses: slackapi/slack-github-action@v1.24.0
+        uses: slackapi/slack-github-action@v2.1.1
         with:
           payload: |
             {