Prepare release 0.9.0

Refs: #5323
Change-Id: Ifd67ae391221916679e79b7a321163792ca3af95
diff --git a/wscript b/wscript
index 0f0ea01..1e18344 100644
--- a/wscript
+++ b/wscript
@@ -4,7 +4,7 @@
 import subprocess
 from waflib import Context, Logs, Utils
 
-VERSION = '0.8.1'
+VERSION = '0.9.0'
 APPNAME = 'ndn-cxx'
 GIT_TAG_PREFIX = 'ndn-cxx-'