Add changelog entry for publishDate schema fix

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: stevelandeydescript

CHANGELOG.md

@@ -10,6 +10,8 @@
 
 ### Fixed
 
+- The output schema rejected data from providers that don't set `publishDate` (like Mise), causing `make-github-issues` and `make-linear-issues` to crash with a ZodError when run against multi-ecosystem output.
+
 ### Removed
 
 ## 0.2.0 - 2026-05-07