[gnome-disk-utility] build: Fix meson issue regarding install_dir

[Kai Lüke <kailueke src gnome org>]

commit 9596c7763d4d853c5f9e9a12e905a0603fd103d6
Author: Iñigo Martínez <inigomartinez gmail com>
Date:   Wed Jul 3 23:03:07 2019 +0200

    build: Fix meson issue regarding install_dir
    
    Although it was available before, the `install_dir` in configured
    files has marked as supported in meson 0.50.
    
    The minimum required version has been bumped so the warning message
    is not shown anymore.

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 1147c7f1..6be18834 100644
--- a/meson.build
+++ b/meson.build
@@ -3,7 +3,7 @@ project(
   version: '3.33.3',
   license: 'GPL2.0',
   default_options: 'buildtype=debugoptimized',
-  meson_version: '>= 0.47.0'
+  meson_version: '>= 0.50.0'
 )
 
 gdu_name = 'gnome-disk-utility'