chore: bump up docker/build-push-action action to v6 (#7236)

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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` |

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### 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

📅 **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.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

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.github/workflows/build-server-image.yml

@@ -223,7 +223,7 @@ jobs:
         uses: ./.github/actions/setup-version
 
       - name: Build graphql Dockerfile
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           push: true

.github/workflows/deploy.yml

@@ -134,7 +134,7 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
       - name: Build front Dockerfile
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           push: true