Bump docker/build-push-action from 5 to 6 (#129)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

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

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

.github/workflows/test.yml

@@ -31,15 +31,15 @@ jobs:
         username: ${{ secrets.DOCKER_USERNAME }}
         password: ${{ secrets.DOCKER_PASSWORD }}
     - name: Build and push p4lang/p4runtime-sh to local registry
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         tags: localhost:5000/p4lang/p4runtime-sh
         push: true
         cache-from: type=gha,scope=p4runtime-sh
         cache-to: type=gha,scope=p4runtime-sh,mode=max
     - name: Build and export p4lang/p4runtime-sh-dev to Docker
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         file: Dockerfile.dev
@@ -58,7 +58,7 @@ jobs:
         docker run $ci_env p4lang/p4runtime-sh-dev bash -c "source venv/bin/activate && nose2 --with-coverage p4runtime_sh config_builders && codecov"
     - name: Build and push p4lang/p4runtime-sh to Dockerhub if needed
       if: ${{ github.repository == 'p4lang/p4runtime-shell' && github.event_name == 'push' }}
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         push: true