configure.ac: bump version to 1.12.90 for open development

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/configure.ac b/configure.ac
index 619d3f6..6398b2a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,6 @@
 m4_define([weston_major_version],  [1])
 m4_define([weston_minor_version],  [12])
-m4_define([weston_micro_version],  [0])
+m4_define([weston_micro_version],  [90])
 m4_define([weston_version],
           [weston_major_version.weston_minor_version.weston_micro_version])
 m4_define([libweston_major_version], [1])