GIT_SILENT Update Appstream for new release

src/data/org.kde.kmail2.appdata.xml

@@ -290,9 +290,9 @@
     <binary>kmail</binary>
   </provides>
   <releases>
+    <release version="5.17.2" date="2021-06-10"/>
     <release version="5.17.1" date="2021-05-13"/>
     <release version="5.17.0" date="2021-04-22"/>
     <release version="5.16.3" date="2021-03-04"/>
-    <release version="5.16.2" date="2021-02-04"/>
   </releases>
 </component>