GIT_SILENT Update Appstream for new release

(cherry picked from commit eec35b60)

src/org.kde.killbots.appdata.xml

@@ -100,10 +100,10 @@
   </provides>
   <launchable type="desktop-id">org.kde.killbots.desktop</launchable>
   <releases>
+    <release version="21.08.3" date="2021-11-04"/>
     <release version="21.08.2" date="2021-10-07"/>
     <release version="21.08.1" date="2021-09-02"/>
     <release version="21.08.0" date="2021-08-12"/>
-    <release version="21.04.3" date="2021-07-08"/>
   </releases>
   <content_rating type="oars-1.1">
     <content_attribute id="violence-cartoon">mild</content_attribute>