Bump docker/build-push-action from 5 to 6 (#42)

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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: John Freeman <john.freeman.opensource@gmail.com>

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -46,7 +46,7 @@ jobs:
             org.opencontainers.image.description=Base container image for development
 
       - name: Build and push Docker image (devcontainer-base)
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ${{ env.DIR_NAME }}
           push: ${{ github.event_name != 'pull_request' }}
@@ -83,7 +83,7 @@ jobs:
             org.opencontainers.image.description=Container image for development with Docker-in-Docker
 
       - name: Build and push Docker image (devcontainer-dind)
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ${{ env.DIR_NAME }}
           push: ${{ github.event_name != 'pull_request' }}
@@ -120,7 +120,7 @@ jobs:
             org.opencontainers.image.description=Container image for development with Kubernetes (K3s)
 
       - name: Build and push Docker image (devcontainer-k8s)
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ${{ env.DIR_NAME }}
           push: ${{ github.event_name != 'pull_request' }}