update changelog

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## master
+## 3.1.9
 
 * Add: support for Python 3.11 + 3.12
 * Drop: support for Python 3.6
@@ -19,6 +19,7 @@
 * Improve: server socket listen code + address format in log
 * Update: documentations + examples
 * Dependency: limit typegard version < 3
+* General: code cosmetics
 
 ## 3.1.8