Log Message:
Update to 1.20.0:

OpenBSD authentication is supported in MATE Screensaver

Full changelog:

Add HiDPI support for lock screen
gs-lock-plug.c: Fix build warning:
WidthOfScreen and HeightOfScreen implementation
restore the correct mate-screensaver-command manpage
fix loop initial declarations
Fix: idle slider display in all languages
drop glib required max version
avoid deprecated gdk_screen_get_width/height
don’t use deprecated gtk_show_uri
Implement OpenBSD authentication using bsd_auth(3).
Bug Fix: g_get_real_name will never return NULL pointer
lock-dialog UI: avoid deprecated widgets
Bug fix: screensaver and lock screen not correctly displayed in configurations \ 
with overlapping monitor geometries
[GTK+3.20] Switch to GdkSeat
Set input purpose for the password entry widget
copy theme dialog: fix build warning about wrong variable type
Translations update