Update docker/build-push-action action to v6 (#77)

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This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
|
[docker/build-push-action](https://togithub.com/docker/build-push-action)
| action | major | `v5` -> `v6` |

---

### Release Notes

<details>
<summary>docker/build-push-action (docker/build-push-action)</summary>

###
[`v6`](https://togithub.com/docker/build-push-action/compare/v5...v6)

[Compare
Source](https://togithub.com/docker/build-push-action/compare/v5...v6)

</details>

---

### Configuration

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every weekday,every weekend" (UTC), Automerge - At any time (no schedule
defined).

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are satisfied.

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rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
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---

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---

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.github/workflows/release.yml

@@ -58,7 +58,7 @@ jobs:
         run: echo "::set-output name=tag::${GITHUB_REF#refs/tags/}"
       - name: Build and push Docker image
         id: push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           push: true