Update changelog

Author: cavasinf

docs/changes/1.x/1.4.0.md

@@ -18,3 +18,5 @@
 - Add test case to make sure vMerge defaults to 'continue' by [@SpraxDev](https://github.com/SpraxDev) in [#2677](https://github.com/PHPOffice/PHPWord/pull/2677)
 
 ### BC Breaks
+
+- TemplateProcessor: Fix 0 considered as empty string. Fixing [#2572](https://github.com/PHPOffice/PHPWord/issues/2572) in [#2617](https://github.com/PHPOffice/PHPWord/pull/2617)