Prepare debian changelog for 4.0.6
diff --git a/debian/changelog b/debian/changelog
index 40e2f7a..e3aa6f7 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,8 +1,8 @@
-cassandra (4.0.6) UNRELEASED; urgency=medium
+cassandra (4.0.6) unstable; urgency=medium
 
   * New release
 
- -- Mick Semb Wever <mck@apache.org>  Tue, 12 Jul 2022 12:16:22 +0200
+ -- Mick Semb Wever <mck@apache.org>  Thu, 18 Aug 2022 20:30:16 +0200
 
 cassandra (4.0.5) unstable; urgency=medium