Update changelog for 3.26.4-1 release

debian/changelog

@@ -1,3 +1,13 @@
+cmake (3.26.4-1) experimental; urgency=medium
+
+  * Do not build with link-time optimization (Closes: #1034873)
+  * Fix obsolete Build-Depend on libncurses5-dev
+  * Bump Standards-Version to 4.6.2
+  * New upstream version 3.26.4
+  * Enable hardening flags
+
+ -- Timo Röhling <roehling@debian.org>  Tue, 23 May 2023 17:38:50 +0200
+
 cmake (3.25.1-1) unstable; urgency=medium
 
   * New upstream version 3.25.1