Wrong 0 exit status code reported on fail to push image to private registry

[rkrasiuk]

Describe the bug
When pushing an image to the private registry with no credentials, waypoint fails with 0 exit code.

➜ waypoint up

» Building...
✓ Initializing Docker client...
✓ Building image...
 │ Successfully tagged waypoint.local/<app name>:latest
✓ Tagging Docker image: waypoint.local/<app name>:latest => <private registry address>:<tag>
❌ Pushing Docker image...
 │ The push refers to repository [<private registry address>]
! unable to stream Docker logs to terminal: denied: Your authorization token has expired. Reauthenticate and try again.

➜ echo $?
0

Steps to Reproduce

project = "project-name"

app "app-name" {
  build {
    use "docker" {
      buildkit = true
      disable_entrypoint = true
    }

    registry {
      use "docker" {
        image = "<private registry address>"
        tag   = gitrefhash()
      }
    } 
  }
}

Expected behavior
Expected non-zero exit code.

Additional context
This gives false positives on running github actions. The final action status is a success whereas the command has failed.

[mitchellh]

Fixed by @krantzinator