chore(deps): update docker/setup-buildx-action action to v3.12.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
docker/setup-buildx-action	action	minor	v3.11.1 → v3.12.0

---

Warning

Some dependencies could not be looked up. Check the warning logs for more information.

---

Release Notes

docker/setup-buildx-action (docker/setup-buildx-action)

v3.12.0

Compare Source

• Deprecate install input by @​crazy-max in #​455
• Bump @​docker/actions-toolkit from 0.62.1 to 0.63.0 in #​434
• Bump brace-expansion from 1.1.11 to 1.1.12 in #​436
• Bump form-data from 2.5.1 to 2.5.5 in #​432
• Bump undici from 5.28.4 to 5.29.0 in #​435

Full Changelog: docker/setup-buildx-action@v3.11.1...v3.12.0

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.

[renovate]

Edited/Blocked Notification

Renovate will not automatically rebase this PR, because it does not recognize the last commit author and assumes somebody else may have edited the PR.

You can manually request rebase by checking the rebase/retry box above.

⚠️ Warning: custom changes will be lost.

[rene-oromtz]

While a minor version bump, seems we've been having a deprecation warning for config-line since v3.2.0:
Warning: Input 'config-inline' has been deprecated with message: Use buildkitd-config-inline instead

As the related workflows does not run when this is bumped, thought on adding the required modification as major release will deprecate this and could be hard to track.

A successful run with this modification can be found here: https://github.com/canonical/testflinger/actions/runs/21681195422

Run docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f
  with:
    cache-binary: false
    buildkitd-config-inline: [registry."docker.io"]
    mirrors = ["https://github-runner-dockerhub-cache.canonical.com:5000/"]
  
    driver: docker-container
    use: true
    keep-state: false
    cleanup: true
    install: false
  env:
    REGISTRY: ghcr.io
    IMAGE_NAME: canonical/testflinger/testflinger-testenv

@ajzobro @pedro-avalos can someone please help to approve this changes? Since I'm the last pusher I can't approve it now

[ajzobro]

LGTM +1