[mutter] configure.ac: Bump API version number

[Jonas Ådahl <jadahl src gnome org>]

commit 962712ddc2dbfc72c7d84d444569832cf7e12b0d
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Feb 21 23:39:13 2018 +0800

    configure.ac: Bump API version number
    
    Better late then never.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/6

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index fb6202a67..721a62fc7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,7 +9,7 @@ m4_define([mutter_version],
 
 m4_define([mutter_plugin_api_version], [3])
 
-m4_define([libmutter_api_version], [1])
+m4_define([libmutter_api_version], [2])
 
 AC_INIT([mutter], [mutter_version],
         [http://bugzilla.gnome.org/enter_bug.cgi?product=mutter])