Bump docker/build-push-action from 6 to 7 (#30)

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/dockerpush.yml

@@ -55,7 +55,7 @@ jobs:
             bervproject/${{ env.IMAGE_NAME }}
             ghcr.io/${{ github.repository }}
       - name: Build and push Docker images
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           context: .
           push: true