appdata: update some URLs

- Add vcs-browser URL.
- Use the new simplified URL for homepage.

These URLs are visible on GNOME Software and Flathub.

More information: https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-url

Part-of: <https://gitlab.gnome.org/GNOME/loupe/-/merge_requests/303>

data/org.gnome.Loupe.metainfo.xml.in.in

@@ -15,10 +15,11 @@
       <li>Accessible presentation of the most important metadata.</li>
     </ul>
   </description>
-  <url type="homepage">https://apps.gnome.org/app/org.gnome.Loupe/</url>
+  <url type="homepage">https://apps.gnome.org/Loupe/</url>
   <url type="bugtracker">https://gitlab.gnome.org/GNOME/loupe/issues</url>
   <url type="translate">https://l10n.gnome.org/module/loupe/</url>
   <url type="donation">https://www.gnome.org/donate/</url>
+  <url type="vcs-browser">https://gitlab.gnome.org/GNOME/loupe</url>
 
   <screenshots>
     <screenshot type="default">