GIT_SILENT Update Appstream for new release

(cherry picked from commit b610d877)

org.kde.Help.appdata.xml

@@ -298,9 +298,9 @@
   </provides>
   <launchable type="desktop-id">org.kde.Help.desktop</launchable>
   <releases>
+    <release version="5.7.6.21082" date="2021-10-07"/>
     <release version="5.7.6.21081" date="2021-09-02"/>
     <release version="5.7.6.21080" date="2021-08-12"/>
     <release version="5.7.6.21043" date="2021-07-08"/>
-    <release version="5.7.6.21042" date="2021-06-10"/>
   </releases>
 </component>