GIT_SILENT Update Appstream for new release

(cherry picked from commit 4e62bfb3)

data/org.kde.kdenlive.appdata.xml

@@ -242,10 +242,10 @@
     </ul>
   </description>
   <releases>
+    <release version="21.12.2" date="2022-02-03"/>
     <release version="21.12.1" date="2022-01-06"/>
     <release version="21.12.0" date="2021-12-09"/>
     <release version="21.08.3" date="2021-11-04"/>
-    <release version="21.08.2" date="2021-10-07"/>
   </releases>
   <url type="homepage">https://kdenlive.org/</url>
   <url type="bugtracker">https://bugs.kde.org</url>