apps-menu: Use "0o" prefix for octal literals

In short, gjs complains that octal escape sequences are deprecated
and advises to use the "0o" prefix for octal literals. Do that to
fix the warning.

https://bugzilla.gnome.org/show_bug.cgi?id=787294

extensions/apps-menu/extension.js

@@ -358,7 +358,7 @@ const DesktopTarget = new Lang.Class({
             (o, res) => {
                 try {
                     let info = o.query_info_finish(res);
-                    let mode = info.get_attribute_uint32(modeAttr) | 0100;
+                    let mode = info.get_attribute_uint32(modeAttr) | 0o100;
 
                     info.set_attribute_uint32(modeAttr, mode);
                     info.set_attribute_string(trustedAttr, 'yes');