[gimp] autotools: bump GEGL dependency to 0.4.28.

[Jehan <jehanp src gnome org>]

commit daea111efc74856fab94bf3ea0fe42cc43cd93f4
Author: bartoszek <bartoszek github bartus 33mail com>
Date:   Sun Dec 20 17:01:00 2020 +0000

    autotools: bump GEGL dependency to 0.4.28.

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index c182fa453c..eec0c7fbd9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -60,7 +60,7 @@ m4_define([fontconfig_required_version], [2.12.4])
 m4_define([freetype2_required_version], [2.1.7])
 m4_define([gdk_pixbuf_required_version], [2.30.8])
 m4_define([gegl_major_minor_version], [0.4])
-m4_define([gegl_micro_version], [27])
+m4_define([gegl_micro_version], [28])
 m4_define([gegl_required_version],
           [gegl_major_minor_version.gegl_micro_version])
 m4_define([gexiv2_required_version], [0.10.6])