Modify CHANGELOG entry [ci skip]

CHANGELOG

@@ -64,7 +64,7 @@ v 8.4.0 (unreleased)
   - Remove leading comma on award emoji when the user is the first to award the emoji (Zeger-Jan van de Weg)
   - Add build artifacts browser
   - Improve UX in builds artifacts browser
-  - Add MySQL limit migration for `data` column in `events` table
+  - Change type of `data` column in `events` table when using MySQL
 v 8.3.4
   - Use gitlab-workhorse 0.5.4 (fixes API routing bug)