[libshumate] meson: fix cross compilation

[Corentin Noël <corentinnoel src gnome org>]

commit d44f2cb3120918f1b1e7a36eb5c0cfa976f2a1d9
Author: Michal Vasilek <michal vasilek cz>
Date:   Tue May 10 12:07:32 2022 +0200

    meson: fix cross compilation

 meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/meson.build b/meson.build
index 4015ca5..0620886 100644
--- a/meson.build
+++ b/meson.build
@@ -81,6 +81,7 @@ if get_option('gtk_doc')
   dependency('gi-docgen',
     version: '>= 2021.1',
     fallback: ['gi-docgen', 'dummy_dep'],
+    native : true,
   )
   gidocgen = find_program('gi-docgen')
 endif