Include SBOM in the container image (#89)

Author: mac641

.github/workflows/docker.yaml

@@ -36,9 +36,13 @@ jobs:
         [ "${GITHUB_EVENT_NAME}" == 'release' ] && echo "tag=${GITHUB_REF##*/}" >> $GITHUB_ENV || true
         [ "${GITHUB_EVENT_NAME}" == 'push' ] && echo "tag=latest" >> $GITHUB_ENV || true
 
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
     - name: Build and push image
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         push: true
+        sbom: true
         tags: ${{ env.REGISTRY }}/metal-stack/cluster-api-metal-stack-controller:${{ env.tag }}