[wing] Post release version bump

[Ignacio Casal Quinteiro <icq src gnome org>]

commit 7c9f3794f225ecad552a1f3798397cfe9c623fad
Author: Ignacio Casal Quinteiro <qignacio amazon com>
Date:   Tue Aug 21 12:25:48 2018 +0200

    Post release version bump

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index c19a301..5d68a95 100644
--- a/meson.build
+++ b/meson.build
@@ -1,5 +1,5 @@
 project('wing', 'c',
-        version: '0.0.20',
+        version: '0.0.21',
         default_options: [
           'buildtype=debugoptimized',
           'warning_level=2'