units: run systemd-sysupdate-update.service with --loop=16

Let's make sure that updates that make further updates available are
fully applied in a single run of the automatic update service.

NEWS

@@ -56,7 +56,7 @@ CHANGES WITH 263 in spe:
           updates are installed, or the specified number of iterations is
           reached. This is useful for updates that make further updates
           available, for example because they ship new or changed transfer
-          files.
+          files. systemd-sysupdate-update.service now uses --loop=16.
 
 CHANGES WITH 262:
 

man/systemd-sysupdate.xml

@@ -483,6 +483,8 @@
         <option>--reboot</option>, the reboot is requested only once, after the last iteration. May not be
         used with <command>acquire</command>.</para>
 
+        <para><filename>systemd-sysupdate-update.service</filename> runs with <option>--loop=16</option>.</para>
+
         <xi:include href="version-info.xml" xpointer="v263"/></listitem>
       </varlistentry>
 

units/systemd-sysupdate-update.service.in

@@ -17,7 +17,7 @@ ConditionVirtualization=!container
 [Service]
 Type=simple
 NotifyAccess=main
-ExecStart={{LIBEXECDIR}}/systemd-sysupdate update --component-all --cleanup=yes
+ExecStart={{LIBEXECDIR}}/systemd-sysupdate update --component-all --cleanup=yes --loop=16
 
 # Keep this sandboxing synchronised with systemd-sysupdate@.service
 CapabilityBoundingSet=CAP_CHOWN CAP_FOWNER CAP_FSETID CAP_MKNOD CAP_SETFCAP CAP_SYS_ADMIN CAP_SETPCAP CAP_DAC_OVERRIDE CAP_LINUX_IMMUTABLE