[geary] Drop meson version req to remain buildable on Ubuntu 19.04

[Michael Gratton <mjog src gnome org>]

commit 031f02c8c99cdbce4ce4cd7e3727771ac79bac31
Author: Michael Gratton <mike vee net>
Date:   Wed Aug 28 19:17:14 2019 +1000

    Drop meson version req to remain buildable on Ubuntu 19.04

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index dbf2469f..35da285c 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project('geary', [ 'vala', 'c' ],
   version: '3.33.1',
   license: 'LGPL2.1+',
-  meson_version: '>= 0.50',
+  meson_version: '>= 0.49',
 )
 
 gnome = import('gnome')