docs(CHANGES): Note removal of setuptools requirement

Author: tony

CHANGES

@@ -14,6 +14,12 @@ $ pip install --user --upgrade --pre libtmux
 
 <!-- Maintainers and contributors: Insert change notes for the next release above -->
 
+_Maintenance only, no bug fixes, or new features_
+
+### Development
+
+- build system: Remove `setuptools` requirement (#495, in related to #493, #494)
+
 ## libtmux 0.22.1 (2023-05-28)
 
 _Maintenance only, no bug fixes, or new features_