Silence noisy build backend output when building metadata

[CAM-Gerlach]

As reported by @wesleybl on #86 , the full (often verbose, especially in the case of Setuptools) build backend output is shown when just extracting the metadata from the project, which is noisy and distracting, taking away from the carefully curated pyroma output. Now, no build backend output is shown (except for errors). This to @wesleybl for doing all the work to report this and propose a solution! If you could somehow share your commit email, I'd ensure the commit was Co-authored-by: you.

Fixes #86

[wesleybl]

Hi @CAM-Gerlach ! Thanks for this PR! I would be happy to see the merge of this. My email is [email protected]. I think it was missing an entry in Changes.

Thanks!

[CAM-Gerlach]

Thanks, I've added you as a co-author on the commit.

I think it was missing an entry in Changes.

As far as I've noticed, @regebro takes care of that himself, but I'm happy to do whatever he wants with that.

[wesleybl]

@regebro can you have a look here please?

[regebro]

I definitely appreciate when I do NOT have to take care of it, and it's a part of the merge request.

[CAM-Gerlach]

Thanks @regebro ; will take note of that for the future :+1: