fix ghcr docker auth

.github/workflows/build-docker-image.yml

@@ -28,7 +28,8 @@ jobs:
         uses: docker/login-action@65b78e6e13532edd9afa3aa52ac7964289d1a9c1
         with:
           registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
+          # username: ${{ github.actor }}
+          username: swarmsim # https://stackoverflow.com/a/70852324 - see comments
           password: ${{ secrets.GITHUB_TOKEN }}
       # This step uses [docker/metadata-action](https://github.com/docker/metadata-action#about) to extract tags and labels that will be applied to the specified image. The `id` "meta" allows the output of this step to be referenced in a subsequent step. The `images` value provides the base name for the tags and labels.
       - name: Extract metadata (tags, labels) for Docker