Release to unstable.

debian/changelog

@@ -1,4 +1,4 @@
-qt6-base (6.4.2+dfsg-18) UNRELEASED; urgency=medium
+qt6-base (6.4.2+dfsg-18) unstable; urgency=medium
 
   [ Helmut Grohne ]
   * Fix FTCBFS: Do build sqlbrowser. (Closes: #1042709)
@@ -9,7 +9,7 @@ qt6-base (6.4.2+dfsg-18) UNRELEASED; urgency=medium
   * Add Add-SH-detection.patch in order to restore SH detection
    (Closes: #1043225).
 
- -- Debian Qt/KDE Maintainers <debian-qt-kde@lists.debian.org>  Tue, 01 Aug 2023 19:47:16 -0300
+ -- Patrick Franz <deltaone@debian.org>  Tue, 08 Aug 2023 08:40:37 +0200
 
 qt6-base (6.4.2+dfsg-17) unstable; urgency=medium