[gnome-panel] lockdown: fix -Wdiscarded-qualifiers warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 30fc14d4036df3b9882ed3eb2abbc92e8f99535c
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Feb 15 22:26:05 2020 +0200

    lockdown: fix -Wdiscarded-qualifiers warning

 gnome-panel/panel-lockdown.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gnome-panel/panel-lockdown.c b/gnome-panel/panel-lockdown.c
index 4bd3915a8..3443bace5 100644
--- a/gnome-panel/panel-lockdown.c
+++ b/gnome-panel/panel-lockdown.c
@@ -57,7 +57,7 @@ G_DEFINE_TYPE_WITH_PRIVATE (PanelLockdown, panel_lockdown, G_TYPE_OBJECT)
 
 static void
 _panel_lockdown_disabled_applets_changed (GSettings     *settings,
-                                          char          *key,
+                                          const char    *key,
                                           PanelLockdown *lockdown)
 {
         if (lockdown->priv->disabled_applets)