Add changelog entry for v1.7.3

Signed-off-by: Matheus Pimenta <[email protected]>
(cherry picked from commit 85d2b8c)

Author: matheuscscp

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 All notable changes to this project are documented in this file.
 
+## 1.7.3
+
+**Release date:** 2025-10-28
+
+This patch release fixes support for SOCKS5 proxy in the controller APIs.
+
+Fixes:
+- Restore SOCKS5 proxy support
+  [#1916](https://github.com/fluxcd/source-controller/pull/1916)
+
 ## 1.7.2
 
 **Release date:** 2025-10-08