don't specify fully qualified docker hub image name

Using a fully qualified tag name doesn't play well with the existing
logic to update the deployed tag. Rather than messing with that logic,
just revert to not speciying the registry for the tags meant for Docker
Hub.

Author: haarg

.github/workflows/build-container.yml

@@ -53,7 +53,7 @@ jobs:
         uses: docker/metadata-action@v5
         with:
           images: |
-            docker.io/${{ github.repository }}
+            ${{ github.repository }}
             ghcr.io/${{ github.repository }}
           flavor: |
             latest=false