Sync debian package version (0.9.28) with acversion

All of this code is from asn1c 0.9.28, so let's make sure
autoconf + debian packaging agree on the version numbering

Change-Id: Ie8dc8f5df7123d4bf7579f6f4e84b7cc33d49607
diff --git a/debian/changelog b/debian/changelog
index f56c11a..20354b0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+libasn1c (0.9.28) UNRELEASED; urgency=low
+
+  * Initial release.
+
+ -- Harald Welte <laforge@gnumonks.org>  Fri, 27 Oct 2017 22:08:03 +0000
+
 libasn1c (0.1.0) UNRELEASED; urgency=low
 
   * Initial release.