Fix an issue number typo in changelog (#3563)

Author: hroncok

docs/changelog.rst

@@ -9,7 +9,7 @@ v4.28.0 (2025-07-20)
 
 Features - 4.28.0
 ~~~~~~~~~~~~~~~~~
-- Added ``constraints`` to allow specifying constraints files for all dependencies. (:issue:`3350`)
+- Added ``constraints`` to allow specifying constraints files for all dependencies. (:issue:`3550`)
 - Allow disabling tox plugins via the ``TOX_DISABLED_EXTERNAL_PLUGINS`` environment variable - by :user:`gaborbernat`. (:issue:`3468`)
 
 Improved Documentation - 4.28.0