chore(deps): update docker/build-push-action action to v4

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
docker/build-push-action	action	major	v3 -> v4

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Release Notes

docker/build-push-action

v4

Compare Source

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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 becomes conflicted, or you tick the rebase/retry checkbox.

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

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

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[nodebb-misty]

💡 Friendly Note

This pull request was made against the develop branch, which is reserved for commits destined for a minor or major release.If your commits simply fixes a bug, please rebase this PR against the master instead.

• patch releases — bug fixes only
• minor releases — new features, enhancements, and bug fixes
• major releases — breaking changes, including all of the above

Thanks!