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

📅 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.

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

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 16.28%. Comparing base (5ad5d16) to head (f7a54d0).
Report is 1 commits behind head on main.

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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1729   +/-   ##
=======================================
  Coverage   16.28%   16.28%           
=======================================
  Files          76       76           
  Lines        4268     4268           
=======================================
  Hits          695      695           
  Misses       3503     3503           
  Partials       70       70           

Flag	Coverage Δ
backend	16.28% <ø> (ø)

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