[7.x](backport #27416) [Metricbeat] CI: update stack to 7.14

[mergify]

This is an automatic backport of pull request #27416 done by Mergify.
Cherry-pick of 2eb4601 has failed:

On branch mergify/bp/7.x/pr-27416
Your branch is up to date with 'origin/7.x'.

You are currently cherry-picking commit 2eb4601695.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   metricbeat/docker-compose.yml
	both modified:   x-pack/metricbeat/docker-compose.yml

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

---

Mergify commands and options

More conditions and actions can be found in the documentation.

You can also trigger Mergify actions by commenting on this pull request:

• @Mergifyio refresh will re-evaluate the rules
• @Mergifyio rebase will rebase this PR on its base branch
• @Mergifyio update will merge the base branch into this PR
• @Mergifyio backport <destination> will backport this PR on <destination> branch

Additionally, on Mergify dashboard you can:

• look at your merge queues
• generate the Mergify configuration with the config editor.

Finally, you can contact us on https://mergify.io/

[botelastic]

This pull request doesn't have a Team:<team> label.

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2021-08-19T10:18:47.466+0000

• Duration: 97 min 29 sec

• Commit: 8c2a73d

Test stats 🧪

Test	Results
Failed	0
Passed	9763
Skipped	2450
Total	12213

Trends 🧪

💚 Flaky test report

Tests succeeded.

Expand to view the summary

Test stats 🧪

Test	Results
Failed	0
Passed	9763
Skipped	2450
Total	12213

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b mergify/bp/7.x/pr-27416 upstream/mergify/bp/7.x/pr-27416
git merge upstream/7.x
git push upstream mergify/bp/7.x/pr-27416