SSH Key Support

When linking a Packer configuration, Terraform configuration, or application to GitHub in Atlas, you can save a private key that is used for authentication when Atlas runs git clone on the linked repository. This is useful when dealing with submodules: Atlas will attempt to use the same private key to authorize clones of git submodules that are referenced from the parent git repository. The SSH key can be attached to a GitHub user or a one-off deploy Key.