ci: bump slackapi/slack-github-action from 2.1.1 to 3.0.3

Bumps [slackapi/slack-github-action](https://github.com/slackapi/slack-github-action) from 2.1.1 to 3.0.3.
- [Release notes](https://github.com/slackapi/slack-github-action/releases)
- [Changelog](https://github.com/slackapi/slack-github-action/blob/main/CHANGELOG.md)
- [Commits](slackapi/slack-github-action@v2.1.1...v3.0.3)

---
updated-dependencies:
- dependency-name: slackapi/slack-github-action
  dependency-version: 3.0.3
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -130,7 +130,7 @@ jobs:
           accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
           environment: ${{ matrix.environment }}
       - if: failure()
-        uses: slackapi/slack-github-action@v2.1.1
+        uses: slackapi/slack-github-action@v3.0.3
         with:
           method: chat.postMessage
           token: ${{ secrets.SLACK_BOT_TOKEN }}