Bump slackapi/slack-github-action from 1.26.0 to 2.0.0

Bumps [slackapi/slack-github-action](https://github.com/slackapi/slack-github-action) from 1.26.0 to 2.0.0.
- [Release notes](https://github.com/slackapi/slack-github-action/releases)
- [Commits](slackapi/slack-github-action@v1.26.0...v2.0.0)

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

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@v1.26.0
+      - uses: slackapi/slack-github-action@v2.0.0
         with:
           channel-id: ${{ secrets.SLACK_CHANNEL_ID }}
           slack-message: "Created discussion comment: ${{ github.event.comment.html_url }}"