JsonDecodeError Exception

[NeilGerring]

If you've got simplejson installed as a python package, the requests package will throw a simplejson.JSONDecodeError exception instead of json.decoder.JSONDecodeError which is currently caught so that the ppa_api can raise different exceptions.

It would be nice if the ppa_api could handle both until the requests package changes this.
See issues: psf/requests#4842 and psf/requests#5794