Bug#993339: reprotest Salsa CI failure due to different creation times

[Christoph Berg]

Re: Rock Storm
> Christoph, I'm CCing you here both because you created the salsa CI
> configuration file back in the day and because you are the latest
> sponsor for this package, in case you feel this should be a blocker for
> Printrun updates.

Since this seems to be a toolchain issue rather than in the package,
don't treat it as a problem. (And even then, it's "only"
reproducibility which should be fixed, but doesn't have to.)

If it's getting too annoying, you could also make failures non-fatal:

reprotest:
  allow_failure: true

Christoph