[polari] appdata: Update links to use HEAD instead of master

[Florian Müllner <fmuellner src gnome org>]

commit 28fce8f59516a2294a7e4e36091b8d599355be23
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Jul 13 20:01:30 2021 +0200

    appdata: Update links to use HEAD instead of master
    
    The former will respect the configured default branch, which allows
    us to change it with less disruption.
    
    https://gitlab.gnome.org/GNOME/polari/-/merge_requests/202

 data/appdata/org.gnome.Polari.appdata.xml.in | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/data/appdata/org.gnome.Polari.appdata.xml.in b/data/appdata/org.gnome.Polari.appdata.xml.in
index fb8c4072..d0e9c2c3 100644
--- a/data/appdata/org.gnome.Polari.appdata.xml.in
+++ b/data/appdata/org.gnome.Polari.appdata.xml.in
@@ -22,19 +22,19 @@
   </description>
   <screenshots>
     <screenshot type="default">
-      <image>https://gitlab.gnome.org/GNOME/polari/raw/master/data/appdata/polari-main.png</image>
+      <image>https://gitlab.gnome.org/GNOME/polari/raw/HEAD/data/appdata/polari-main.png</image>
     </screenshot>
     <screenshot>
-      <image>https://gitlab.gnome.org/GNOME/polari/raw/master/data/appdata/polari-user-list.png</image>
+      <image>https://gitlab.gnome.org/GNOME/polari/raw/HEAD/data/appdata/polari-user-list.png</image>
     </screenshot>
     <screenshot>
-      <image>https://gitlab.gnome.org/GNOME/polari/raw/master/data/appdata/polari-join-dialog.png</image>
+      <image>https://gitlab.gnome.org/GNOME/polari/raw/HEAD/data/appdata/polari-join-dialog.png</image>
     </screenshot>
     <screenshot>
-      <image>https://gitlab.gnome.org/GNOME/polari/raw/master/data/appdata/polari-connection.png</image>
+      <image>https://gitlab.gnome.org/GNOME/polari/raw/HEAD/data/appdata/polari-connection.png</image>
     </screenshot>
     <screenshot>
-      
<image>https://gitlab.gnome.org/GNOME/polari/raw/master/data/appdata/polari-connection-properties.png</image>
+      
<image>https://gitlab.gnome.org/GNOME/polari/raw/HEAD/data/appdata/polari-connection-properties.png</image>
     </screenshot>
   </screenshots>
   <launchable type="desktop-id">org.gnome.Polari.desktop</launchable>