chore(deps): bump docker/build-push-action from 6 to 7 (#348)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 6 to 7.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v6...v7)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -47,7 +47,7 @@ jobs:
         shell: bash
 
       - name: Build Docker image (amd64, for smoke test)
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           platforms: linux/amd64
           context: .
@@ -65,7 +65,7 @@ jobs:
         timeout-minutes: 1
 
       - name: Build and push multi-platform Docker image
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           platforms: linux/amd64,linux/arm/v7,linux/arm64/v8
           context: .