Acceptance tests fail

When I open a PR, acceptance tests fail, I think because the puppet repo key has expired.

```
Err:2 http://nightlies.puppet.com/apt noble InRelease
  The following signatures were invalid: EXPKEYSIG 4528B6CD9E61EF26 Puppet, Inc. Release Key (Puppet, Inc. Release Key) <release@puppet.com>
```


I guess the "real" fix is to update the `puppet_litmus` gem