Update debian changelog

Author: anoadragon453

debian/changelog

@@ -1,3 +1,11 @@
+matrix-synapse-py3 (1.139.0~rc2+nmu1) UNRELEASED; urgency=medium
+
+  * The licensing specifier has been updated to add an optional
+    `LicenseRef-Element-Commercial` license. The code was already licensed in
+    this manner - the debian metadata was just not updated to reflect it.
+
+ -- Synapse Packaging team <packages@matrix.org>  Thu, 25 Sep 2025 12:07:17 +0100
+
 matrix-synapse-py3 (1.139.0~rc2) stable; urgency=medium
 
   * New Synapse release 1.139.0rc2.