[gegl] post-release version bump

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 523ababc58031f2e4dea844084a05a02cc504de6
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Jan 17 16:54:43 2020 +0100

    post-release version bump

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 9d5b48448..4a32e03ce 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project('gegl',
   'c', 'cpp',
   license: 'GPL3+',
-  version: '0.4.20',
+  version: '0.4.21',
   meson_version: '>=0.50.0',
   default_options: [
     'c_std=gnu11',