[gtksourceview] build: bump development version

[Christian Hergert <chergert src gnome org>]

commit 8bc8d0eea2cbe9110812dcc99aa3ab4854cd448a
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jul 15 16:32:30 2021 -0700

    build: bump development version
    
    We've done a lot of development already this cycle, and we need to ensure
    that it is represented in the version number.

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 9e712957..3ef77cda 100644
--- a/meson.build
+++ b/meson.build
@@ -1,5 +1,5 @@
 project('gtksourceview', 'c',
-          version: '5.0.0',
+          version: '5.1.0',
           license: 'LGPL-2.1-or-later',
     meson_version: '>= 0.53.0',
   default_options: [ 'c_std=gnu99',