Singularity pull and build

Hi, how do I build a singularity container using GitHub packages? I created a token with read-only access to packages and then tried the following.

export GITHUB_TOKEN=1dc02c2910997b4f271d3c76df789f39395ee8df
export CR_PAT=$GITHUB_TOKEN #just in case
singularity build sneakernet.0.11.6.sif docker://

and it returned the following message

WARNING: 'nodev' mount option set on /scratch, it could be a source of failure during build process
INFO:    Starting build...
FATAL:   While performing build: conveyor failed to get: Error reading manifest docker-multistage in unauthorized: Your request could not be authenticated by the GitHub Packages service. Please ensure your access token is valid and has the appropriate scopes configured.

note: The GITHUB_TOKEN was modified for public consumption and has been deleted anyway as a precaution.

For singularity use, don’t try to use the service . See the GitHub Container Registry docs for info on getting started. GHCR is a standards based approach that can do a lot more than the Packages Docker service.