To help support a wider array of container registries it would be help to support more authentication mechanisms than just username/password. Several of the major container registries no longer support u/p authentication.
Token based authentication seems to be supported by all major container registries (Docker, AWS, Azure and GCP). This would be a good target to help drive adoption of VoltStack.
https://cloud.google.com/container-registry/docs/advanced-authentication
https://docs.aws.amazon.com/AmazonECR/latest/userguide/registry_auth.html
https://docs.microsoft.com/en-us/azure/container-registry/container-registry-authentication
https://docs.docker.com/docker-hub/access-tokens/