hydra: change updater time

hosts/containers/hydra/updater.nix

@@ -42,6 +42,8 @@
   systemd.timers.updater = {
     partOf = [ "updater.service" ];
     wantedBy = [ "timers.target" ];
-    timerConfig.OnCalendar = "daily";
+    # update flake.lock daily at 10am so that systems are freshly
+    # built by afternoon
+    timerConfig.OnCalendar = "10:00";
   };
 }