Add suspend to polybar menu

.config/polybar/modules

@@ -169,6 +169,8 @@ menu-0-1 = reboot
 menu-0-1-exec = menu-open-2
 menu-0-2 = logout
 menu-0-2-exec = menu-open-3
+menu-0-3 = suspend
+menu-0-3-exec = menu-open-4
 
 menu-1-0 = shutdown
 menu-1-0-exec = poweroff
@@ -178,3 +180,6 @@ menu-2-0-exec = reboot
 
 menu-3-0 = logout
 menu-3-0-exec = bspc quit
+
+menu-4-0 = suspend
+menu-4-0-exec = systemctl suspend