docs: update changelog date to 2026-05-04

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Zack Koppert <zkoppert@github.com>

Author: zkoppert

HISTORY.md

@@ -1,4 +1,4 @@
-## 6.0.0 - 2026-04-22
+## 6.0.0 - 2026-05-04
 
 ### Breaking