build(deps): bump slackapi/slack-github-action from 1.27.0 to 2.0.0 in the github-actions group (elastic#14656)

* build(deps): bump slackapi/slack-github-action

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


Updates `slackapi/slack-github-action` from 1.27.0 to 2.0.0
- [Release notes](https://github.com/slackapi/slack-github-action/releases)
- [Commits](slackapi/slack-github-action@37ebaef...485a9d4)

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

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

* fix support for the slack 2.0

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Victor Martinez <[email protected]>

Author: dependabot[bot]

.github/workflows/benchmarks.yml

@@ -256,13 +256,14 @@ jobs:
 
       # Notify result to Slack only on schedule (nightly run)
       - if: github.event_name == 'schedule'
-        uses: slackapi/slack-github-action@37ebaef184d7626c5f204ab8d3baff4262dd30f0 # v1.27.0
-        env:
-          SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
+        uses: slackapi/slack-github-action@485a9d42d3a73031f12ec201c457e2162c45d02d # v2.0.0
         with:
-          channel-id: "#apm-server"
+          method: chat.postMessage
+          token: ${{ secrets.SLACK_BOT_TOKEN }}
           payload: |
             {
+                "channel":  "#apm-server",
+                "text": "${{ github.event_name == 'schedule' && 'Nightly' || '' }} APM Server benchmarks succesfully executed!",
                 "blocks": [
                     {
                         "type": "section",