String changes in gnome-software

Hi,

As per the string announcement period, here's a quick heads up about
string changes in gnome-software 3.27.90 that we just released:

The big change is that we've renamed the Software Sources dialog to
Software Repositories, and it also got redesigned, changing pretty much
every string in that dialog.

In addition, we also changed "sources" -> "repositories" in various
other parts in the code base.

Sorry for the disruption and I hope I haven't made too many translators
unhappy. (Also, thanks a lot! It's awesome to have gnome-software
translated into so many languages.)

-- 
Thanks,
Kalev