Bump docker/build-push-action from 2 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 2 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v2...v6)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci-ifcopenshell-docker.yml

@@ -113,7 +113,7 @@ jobs:
         password: ${{ secrets.DOCKER_HUB_TOKEN }}
     - 
       name: Build container image
-      uses: docker/build-push-action@v2
+      uses: docker/build-push-action@v6
       with: 
         context: artifacts
         repository: aecgeeks/ifcopenshell