Cleanup swallows exit codes

[r-vdp]

Describe the bug

When doing github-deploy cleanup <...> -- cmd and cmd exits uncleanly, github-deploy swallows the exit code and exits cleanly.
This makes it hard to know that something went wrong and makes things like github actions show green checks while actually there was a failure.

This happens because the main loop in the code for cleanup does check the exit code, but when it's non-zero it just logs a message and continues, without tracking the fact that there was a failure.

To Reproduce

Steps to reproduce the behavior:

1. ...
2. ...

Expected behavior

Exit uncleanly if at least one action didn't exit cleanly.

System information

Additional context

[zimbatm]

What error did you see exactly?

It would help because log.Fatalf also exits the process with an error code.

[r-vdp]

The invoked command was Terraform (wrapped in just and terragrunt), which failed during planning. I can check what's the exact exit code that gets returned, but it's definitely not 0.