Cannot push docker image to container registry because our organization name ends with hyphen

Hi !

I want to use GitHub package to publish container images.
This page says we should tag our images with format ghcr.io/OWNER/IMAGE_NAME.

However, I belong to a GitHub Organization which the name ends with - (hyphen), and I cannot create tags.
Commands such as docker tag <imagename> ghcr.io/org-/image-name:latest causes error with message Error parsing reference: "ghcr.io/org-/image-name:latest" is not a valid repository/tag: invalid reference format.

Are there any options for using GitHub container registry for organization whose name ends with hyphen?

Thanks, regards.