fix: bump the settings version to 6

I was misled by messy code of the old extension to believe that its
schema vrsion was 4, but it was actually 5, so I re-used the old version
code and settings didn't get migrated.

resources/schemas/org.gnome.shell.extensions.rounded-window-corners-reborn.gschema.xml

@@ -6,7 +6,8 @@
   >
 
     <key name="settings-version" type="u">
-      <default>5</default>
+      <!-- This gets set to the correct value when preferences are migrated -->
+      <default>0</default>
     </key>
 
     <key name="blacklist" type="as">

src/utils/settings.ts

@@ -122,7 +122,7 @@ export function bindPref(
  * @param prefs the GSettings object to clean.
  */
 function resetOutdated(prefs: Gio.Settings) {
-    const lastVersion = 5;
+    const lastVersion = 6;
     const currentVersion = prefs
         .get_user_value('settings-version')
         ?.recursiveUnpack();