Update XscreenSaver lock screen to 21.04.

debian/changelog

@@ -1,3 +1,9 @@
+lubuntu-default-settings (21.04.1) UNRELEASED; urgency=medium
+
+  * Update XscreenSaver lock screen to 21.04.
+
+ -- Dan Simmons <kc2bez@lubuntu.me>  Sun, 03 Jan 2021 14:45:56 -0500
+
 lubuntu-default-settings (20.10.1) groovy; urgency=medium
 
   * Added SAL_VCL_QT5_USE_CAIRO=true env variable in session.conf. LP: #1895216

src/usr/lib/X11/app-defaults/XScreenSaver

@@ -604,4 +604,4 @@ xscreensaver.Dialog.borderWidth:            1
 xscreensaver.Dialog.shadowThickness:        2
 
 ! Some credits to Lubuntu also please. :)
-xscreensaver.passwd.heading.label:		Lubuntu 20.04
+xscreensaver.passwd.heading.label:		Lubuntu 21.04