Update docker/build-push-action action to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
docker/build-push-action	action	major	v5 -> v6

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Release Notes

docker/build-push-action (docker/build-push-action)

v6

Compare Source

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Configuration

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

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

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[github-actions]

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[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.