chore: update CHANGES-5.0.md

CHANGES-5.0.md

@@ -3,6 +3,7 @@
 ## Bug fixes
 
 * Fix exhook `client.authorize` never being execauted. [#8780](https://github.com/emqx/emqx/pull/8780)
+* Fix JWT plugin don't support non-integer timestamp claims. [#8867](https://github.com/emqx/emqx/pull/8867)
 
 ## Enhancements