Add AppStream metainfo file
This file is taken from the Flathub package, as of https://github.com/flathub/org.pulseaudio.pavucontrol/pull/31 where I have adjusted the name & summary to conform to Flathub's rules. In particular:
- The name must be no more than 20 characters, so I have used “Volume Control” to match the window title and GenericName
- The summary must be no more than 35 characters. It is actually very
hard to squeeze the crucial information that you can adjust both
applications' and devices' volume levels into 35 characters, so this
is the best I could do. I then noticed while preparing this patch that
the Comment in the .desktop file (which the appstream specification
says is “roughly equivalent” to the
) is just “Adjust the volume level”. IMO “Adjust the volume level” contains no more information than the name “Volume Control”.
I also added the release notes for 5.0 which are not in the Flathub build.
Fixes #127 (closed)