Support for singularity container

[saw235]

Is there anyway github actions can support using singularity container? https://docs.sylabs.io/guides/3.0/user-guide/singularity_and_docker.html

[nikola-jokic]

Hey @saw235,

Unfortunately, we are not planning to support singularity. The idea was to create docker and k8s hooks as a base, that can cover most cases. If you want to change the way they operate, you can use it as a starting point or a guide to implement your own hooks :relaxed:.